U.S. patent application number 15/163070 was filed with the patent office on 2016-09-15 for processes for treating magnesium-containing materials.
The applicant listed for this patent is ORBITE TECHNOLOGIES INC.. Invention is credited to Richard BOUDREAULT, Hubert DUMONT, Marie-Maxime LABRECQUE-GILBERT, Denis PRIMEAU.
Application Number | 20160265082 15/163070 |
Document ID | / |
Family ID | 50386741 |
Filed Date | 2016-09-15 |
United States Patent
Application |
20160265082 |
Kind Code |
A1 |
BOUDREAULT; Richard ; et
al. |
September 15, 2016 |
PROCESSES FOR TREATING MAGNESIUM-CONTAINING MATERIALS
Abstract
The disclosed processes can be effective for treating various
materials comprising several different metals. These materials can
be leached with HCl for obtaining a leachate and a solid. Then,
they can be separated from one another and a first metal can be
isolated from the leachate. Then, a second metal can further be
isolated from the leachate. The first and second metals can each be
substantially selectively isolated from the leachate. This can be
done by controlling the temperature of the leachate, adjusting pH,
further reacting the leachate with HCl, etc. The metals that can be
recovered in the form of metal chlorides can eventually be
converted into the corresponding metal oxides, thereby allowing for
recovering HCl. The various metals can be chosen from aluminum,
iron, zinc, copper, gold, silver, molybdenum, cobalt, magnesium,
lithium, manganese, nickel, palladium, platinum, thorium,
phosphorus, uranium, titanium, rare earth element and rare
metals.
Inventors: |
BOUDREAULT; Richard;
(St-Laurent, CA) ; PRIMEAU; Denis; (Ste-Julie,
CA) ; LABRECQUE-GILBERT; Marie-Maxime; (Laval,
CA) ; DUMONT; Hubert; (Laval, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ORBITE TECHNOLOGIES INC. |
St-Laurent |
|
CA |
|
|
Family ID: |
50386741 |
Appl. No.: |
15/163070 |
Filed: |
May 24, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14429017 |
Mar 18, 2015 |
9353425 |
|
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PCT/CA2013/000830 |
Sep 26, 2013 |
|
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15163070 |
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61705898 |
Sep 26, 2012 |
|
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61713795 |
Oct 15, 2012 |
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61726971 |
Nov 15, 2012 |
|
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61837715 |
Jun 21, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C01F 5/00 20130101; C01G
49/06 20130101; C22B 3/10 20130101; C22B 3/46 20130101; C01G 1/02
20130101; C22B 21/0015 20130101; C01G 1/06 20130101; C22B 7/02
20130101; C01B 7/0706 20130101; C21B 15/00 20130101; C01B 9/02
20130101; C01G 49/10 20130101; C22B 23/0469 20130101; C01F 7/22
20130101; Y02P 20/129 20151101; C22B 7/007 20130101; C22B 7/04
20130101; C22B 23/0423 20130101; C01F 5/10 20130101; C22B 26/22
20130101; C22B 21/0023 20130101; C01B 33/126 20130101; C01G 23/0536
20130101 |
International
Class: |
C22B 3/10 20060101
C22B003/10; C22B 7/00 20060101 C22B007/00; C21B 15/00 20060101
C21B015/00; C22B 7/02 20060101 C22B007/02; C22B 3/00 20060101
C22B003/00; C22B 21/00 20060101 C22B021/00; C22B 3/46 20060101
C22B003/46; C22B 7/04 20060101 C22B007/04 |
Claims
1. A process for treating a magnesium-containing material, said
process comprising: leaching the magnesium-containing material with
HCl so as to obtain a leachate comprising magnesium ions and ions
from at least one metal and a solid, and separating said solid from
said leachate; and precipitating said at least one metal by
reacting said leachate with a precipitating agent so as to obtain a
liquid comprising said magnesium ions and a precipitate comprising
said precipitated at least one metal, and separating said
precipitate from said liquid.
2. The process of claim 1, wherein said process comprises
substantially selectively precipitating said magnesium ions by
reacting said liquid with said precipitating agent.
3. The process of claim 1, wherein said precipitating agent is a
base.
4. The process of claim 2, wherein said precipitating agent is
Mg(OH).sub.2.
5. The process of claim 1, wherein said magnesium-containing
material is serpentine.
6. The process of claim 1, wherein said magnesium-containing
material is asbestos.
7. The process of claim 1, wherein said at least one metal is
nickel.
8. The process of claim 1, wherein said at least one metal is
cobalt.
9. The process of claim 1, wherein said at least one metal is
iron.
10. The process of claim 1, wherein said at least one metal is
aluminum.
11. The process of claim 1, wherein said process comprises:
precipitating said a first metal by reacting said leachate with a
precipitating agent so as to obtain said liquid comprising said
magnesium ions and said precipitate comprising said precipitated
first one metal, and separating said precipitate from said liquid;
and precipitating a second metal by reacting said liquid with a
precipitating agent so as to obtain another liquid comprising said
magnesium ions and another precipitate comprising said precipitated
second metal, and separating said another precipitate from said
another liquid.
12. The process of claim 11, wherein said first metal is iron and
said second metal is nickel.
13. The process of claim 12, wherein said precipitating agent is a
base.
14. The process of claim 11, wherein said process further comprises
reacting said another liquid with HCl so as to precipitate said
magnesium ions in the form of MgCl.sub.2.
15. A process for treating a magnesium-containing material, said
process comprising: leaching the magnesium-containing material with
HCl so as to obtain a leachate comprising magnesium ions and ions
from at least one metal and a solid, and separating said solid from
said leachate; controlling the concentration of HCl in the leachate
and/or the temperature of the leachate so as to precipitate the
first metal in the form of a chloride, and removing the precipitate
from the leachate; and controlling the concentration of HCl in the
leachate and/or the temperature of the leachate so as to
precipitate a second metal in the form of a chloride, and removing
the precipitate from the leachate.
16. The process of claim 15, wherein said process comprises:
controlling the concentration of HCl in the leachate so as to
precipitate the first metal in the form of a chloride, and removing
the precipitate from the leachate; and controlling the
concentration of HCl in the leachate so as to precipitate a second
metal in the form of a chloride, and removing the precipitate from
the leachate.
17. The process of claim 16, wherein said process further comprises
controlling the concentration of HCl in the leachate so as to
precipitate said magnesium ions in the form of MgCl.sub.2.
18. The process of claim 17, wherein said process further comprises
reacting said magnesium ions with HCl so as to precipitate said
magnesium ions in the form of MgCl.sub.2.
19. The process of claim 16, wherein said first metal is iron and
said second metal is nickel.
20. The process of claim 17, wherein said first metal is iron and
said second metal is nickel.
21. The process of claim 17, wherein said process further comprises
heating said MgCl.sub.2.
22. The process of claim 20, wherein said process further comprises
heating said MgCl.sub.2 in the presence of HCl.
23. The process of claim 20, wherein said process further comprises
heating said MgCl.sub.2 so as to convert said MgCl.sub.2 into MgO.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/429,017 filed on Mar. 18, 2015, that is a
35 USC 371 national stage entry of PCT/CA2013/000830 filed on Sep.
26, 2013 and which claims priority on U.S. 61/705,898 filed on Sep.
26, 2012, on U.S. 61/713,795 filed on Oct. 15, 2012; on U.S.
61/726,971 filed on Nov. 15, 2012; on U.S. 61/837,715 filed on Jun.
21, 2013. These documents are hereby incorporated by reference in
their entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to improvements in the field
of chemistry applied to the treatment of various ores. For example,
it relates to processes for treating materials comprising at least
one metal chosen from aluminum, iron, zinc, copper, gold, silver,
molybdenum, cobalt, magnesium, lithium, manganese, nickel,
palladium, platinum, thorium, phosphorus, uranium and titanium,
and/or at least one rare earth element and/or at least one rare
metal.
BACKGROUND OF THE DISCLOSURE
[0003] There have been several known processes for the production
of alumina, titanium oxide, magnesium oxide, hematite, nickel,
cobalt rare earth elements, rare metals etc. Many of them have the
disadvantage of being inefficient to segregate and extract value
added secondary products, thus leaving an important environmental
impact.
SUMMARY OF THE DISCLOSURE
[0004] According to one aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0005] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0006] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; [0007] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3 and recovering gaseous HCl so-produced; and
[0008] recycling the gaseous HCl so-produced by contacting it with
water so as to obtain a composition having a concentration higher
than HCl azeotrope concentration (20.2 weight %) and reacting the
composition with a further quantity of aluminum-containing material
so as to leaching it.
[0009] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0010] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0011] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; and [0012] optionally
reacting the precipitate with a base; and [0013] heating the
precipitate under conditions effective for converting it into
Al.sub.2O.sub.3.
[0014] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0015] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0016] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; and [0017] optionally
reacting the precipitate with a base; and [0018] heating the
precipitate under conditions effective for converting it into
Al.sub.2O.sub.3.
[0019] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0020] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0021] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; [0022] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3 and recovering gaseous HCl so-produced; and
[0023] recycling the gaseous HCl so-produced by contacting it with
water so as to obtain a composition having a concentration of about
18 to about 45 weight % or about 25 to about 45 weight % and
reacting the composition with a further quantity of
aluminum-containing material so as to leaching it.
[0024] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0025] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0026] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; [0027] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3 and recovering gaseous HCl so-produced; and
[0028] recycling the gaseous HCl so-produced by contacting it with
water so as to obtain a composition having a concentration of about
18 to about 45 weight % or about 25 to about 45 weight % and using
the composition for leaching the aluminum-containing material.
[0029] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0030] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0031] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; [0032] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3 and recovering gaseous HCl so-produced; and
[0033] recycling the gaseous HCl so-produced by contacting it with
the leachate so as to precipitate the aluminum ions in the form of
AlCl.sub.3.6H.sub.2O.
[0034] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0035] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0036] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; and [0037] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3.
[0038] According to another aspect, there is provided a process for
preparing alumina and optionally other products, the process
comprising: [0039] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0040] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; and [0041] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3 and optionally recovering gaseous HCl
so-produced.
[0042] According to one aspect, there is provided a process for
preparing aluminum and optionally other products, the process
comprising: [0043] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0044] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; [0045] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3; and [0046] converting Al.sub.2O.sub.3 into
aluminum.
[0047] According to another aspect, there is provided a process for
preparing aluminum and optionally other products, the process
comprising: [0048] leaching an aluminum-containing material with
HCl so as to obtain a leachate comprising aluminum ions and a
solid, and separating the solid from the leachate; [0049] reacting
the leachate with HCl so as to obtain a liquid and a precipitate
comprising the aluminum ions in the form of AlCl.sub.3, and
separating the precipitate from the liquid; [0050] heating the
precipitate under conditions effective for converting AlCl.sub.3
into Al.sub.2O.sub.3 and optionally recovering gaseous HCl
so-produced; and converting Al.sub.2O.sub.3 into aluminum.
[0051] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0052] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0053] reacting the
leachate with HCl so as to obtain a liquid and a precipitate
comprising a chloride of the first metal, and separating the
precipitate from the liquid; and [0054] heating the precipitate
under conditions effective for converting the chloride of the first
metal into an oxide of the first metal.
[0055] According to another aspect, there is provided a process for
treating serpentine, the process comprising: [0056] leaching
serpentine with HCl so as to obtain a leachate comprising magnesium
ions and a solid, and separating the solid from the leachate;
[0057] reacting the leachate with HCl so as to obtain a liquid and
a precipitate comprising MgCl.sub.2, and separating the precipitate
from the liquid; and [0058] heating the precipitate under
conditions effective for converting MgCl.sub.2 into MgO and
optionally recovering gaseous HCl so-produced.
[0059] According to another aspect, there is provided a process for
treating serpentine, the process comprising: [0060] leaching
serpentine with HCl so as to obtain a leachate comprising magnesium
ions and a solid, and separating the solid from the leachate;
[0061] reacting the leachate with HCl so as to obtain a liquid and
a precipitate comprising MgCl.sub.2, and separating the precipitate
from the liquid; and [0062] heating the precipitate under
conditions effective for converting MgCl.sub.2 into MgO.
[0063] According to another aspect, there is provided process for
treating a magnesium-containing material, the process comprising:
[0064] leaching the magnesium-containing material with HCl so as to
obtain a leachate comprising magnesium ions and a solid, and
separating the solid from the leachate; [0065] reacting the
leachate with HCl so as to obtain a liquid and a precipitate
comprising MgCl.sub.2, and separating the precipitate from the
liquid; and [0066] heating the precipitate under conditions
effective for converting MgCl.sub.2 into MgO and optionally
recovering gaseous HCl so-produced.
[0067] According to another aspect, there is provided a process for
treating a magnesium-containing material, the process comprising:
[0068] leaching the magnesium-containing material with HCl so as to
obtain a leachate comprising magnesium ions and ions from at least
one metal and a solid, and separating the solid from the leachate;
and [0069] precipitating the at least one metal by reacting the
leachate with a precipitating agent so as to obtain a liquid
comprising the magnesium ions and a precipitate comprising the
precipitated at least one metal, and separating the precipitate
from the liquid.
[0070] According to another aspect, there is provided a process for
treating a material comprising magnesium and at least one other
metal, the process comprising: [0071] leaching the material with
HCl so as to obtain a leachate comprising magnesium ions and ions
from the at least one other metal and a solid, and separating the
solid from the leachate; and [0072] precipitating the at least one
other metal by reacting the leachate with a precipitating agent so
as to obtain a liquid comprising the magnesium ions and a
precipitate comprising the precipitated at least one metal, and
separating the precipitate from the liquid; [0073] treating the
liquid so as to cause precipitation of Mg(OH).sub.2; and [0074]
treating the precipitate so as to substantially selectively isolate
the at least one metal therefrom.
[0075] According to another aspect, there is provided a process for
preparing alumina, the process comprising: [0076] leaching an
aluminum-containing material with HCl so as to obtain a leachate
comprising aluminum ions, magnesium ions and a solid, and
separating the solid from the leachate; [0077] substantially
selectively precipitating MgCl.sub.2 from the leachate and removing
the MgCl.sub.2 from the leachate; [0078] reacting the leachate with
HCl so as to obtain a liquid and a precipitate comprising the
aluminum ions in the form of AlCl.sub.3, and separating the
precipitate from the liquid; [0079] heating the precipitate under
conditions effective for converting AlCl.sub.3 into Al.sub.2O.sub.3
and optionally recovering gaseous HCl so-produced; and [0080]
heating the MgCl.sub.2 under conditions effective for converting it
into MgO and optionally recovering gaseous HCl so-produced.
[0081] According to another aspect, there is provided a process for
preparing aluminum, the process comprising: [0082] leaching an
aluminum-containing material with HCl so as to obtain a leachate
comprising aluminum ions, magnesium ions and a solid, and
separating the solid from the leachate; [0083] substantially
selectively precipitating MgCl.sub.2 from the leachate and removing
the MgCl.sub.2 from the leachate; [0084] reacting the leachate with
HCl so as to obtain a liquid and a precipitate comprising the
aluminum ions in the form of AlCl.sub.3, and separating the
precipitate from the liquid; [0085] heating the MgCl.sub.2 under
conditions effective for converting it into MgO and optionally
recovering gaseous HCl so-produced; [0086] heating the precipitate
under conditions effective for converting AlCl.sub.3 into
Al.sub.2O.sub.3 and optionally recovering gaseous HCl so-produced;
and [0087] converting the Al.sub.2O.sub.3 into alumina.
[0088] According to another aspect, there is provided a process for
preparing alumina, the process comprising: [0089] leaching an
aluminum-containing material with HCl so as to obtain a leachate
comprising aluminum ions, magnesium ions and a solid, and
separating the solid from the leachate; [0090] substantially
selectively precipitating MgCl.sub.2 from the leachate and removing
the MgCl.sub.2 from the leachate; [0091] reacting the leachate with
HCl so as to obtain a liquid and a precipitate comprising the
aluminum ions in the form of AlCl.sub.3, and separating the
precipitate from the liquid; [0092] optionally treating the
precipitate with a base; [0093] heating the precipitate under
conditions effective for converting the precipitate into
Al.sub.2O.sub.3 and optionally recovering gaseous HCl so-produced;
and heating the MgCl.sub.2 under conditions effective for
converting it into MgO and optionally recovering gaseous HCl
so-produced.
[0094] According to another aspect, there is provided a process for
preparing aluminum, the process comprising: [0095] leaching an
aluminum-containing material with HCl so as to obtain a leachate
comprising aluminum ions, magnesium ions and a solid, and
separating the solid from the leachate; [0096] substantially
selectively precipitating MgCl.sub.2 from the leachate and removing
the MgCl.sub.2 from the leachate; [0097] reacting the leachate with
HCl so as to obtain a liquid and a precipitate comprising the
aluminum ions in the form of AlCl.sub.3, and separating the
precipitate from the liquid; [0098] optionally treating the
precipitate with a base; [0099] heating the MgCl.sub.2 under
conditions effective for converting it into MgO and optionally
recovering gaseous HCl so-produced; [0100] heating the precipitate
under conditions effective for converting the precipitate into
Al.sub.2O.sub.3 and optionally recovering gaseous HCl so-produced;
and [0101] converting the Al.sub.2O.sub.3 into alumina.
[0102] According to another aspect, there is provided a process for
treating serpentine, the process comprising: [0103] leaching
serpentine with HCl so as to obtain a leachate comprising magnesium
ions and a solid, and separating the solid from the leachate;
[0104] controlling the temperature of the leachate so as to
substantially selectively precipitate the magnesium ions in the
form of magnesium chloride, and removing the precipitate from the
leachate, thereby obtaining a liquid; and [0105] heating the
MgCl.sub.2 under conditions effective for converting MgCl.sub.2
into MgO and optionally recovering gaseous HCl so-produced.
[0106] According to another aspect, there is provided a process for
treating a magnesium-containing material, the process comprising:
[0107] leaching the magnesium-containing material with HCl so as to
obtain a leachate comprising magnesium ions, and a solid, and
separating the solid from the leachate; [0108] controlling the
temperature of the leachate so as to substantially selectively
precipitate the magnesium ions in the form of magnesium chloride,
and removing the precipitate from the leachate, thereby obtaining a
liquid; and [0109] heating the MgCl.sub.2 under conditions
effective for converting MgCl.sub.2 into MgO and optionally
recovering gaseous HCl so-produced.
[0110] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0111] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0112] controlling the
temperature of the leachate so as to precipitate the the first
metal in the form of a chloride, and removing the precipitate from
the leachate, [0113] reacting the leachate with HCl so as to obtain
a liquid and a precipitate comprising a chloride of the second
metal, and separating the precipitate from the liquid; [0114]
optionally heating the chloride of the first metal under conditions
effective for converting it into an oxide of the first metal, and
optionally recovering the so-produced HCl; and [0115] optionally
heating the chloride of the second metal under conditions effective
for converting it into an oxide of the second metal, and optionally
recovering the so-produced HCl.
[0116] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0117] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0118] controlling the
temperature of the leachate so as to precipitate the the first
metal in the form of a chloride, and removing the precipitate from
the leachate; [0119] controlling the temperature of the leachate so
as to precipitate the the second metal in the form of a chloride,
and removing the precipitate from the leachate; [0120] optionally
heating the chloride of the first metal under conditions effective
for converting it into an oxide of the first metal, and optionally
recovering the so-produced HCl; and [0121] optionally heating the
chloride of the second metal under conditions effective for
converting it into an oxide of the second metal, and optionally
recovering the so-produced HCl.
[0122] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0123] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0124] reacting the
leachate with HCl so as to obtain a precipitate comprising the
first metal in the form of a chloride, and removing the precipitate
from the leachate; [0125] reacting the leachate with HCl so as to
obtain a precipitate comprising a second metal in the form of a
chloride, and removing the precipitate from the leachate; [0126]
optionally heating the chloride of the first metal under conditions
effective for converting it into an oxide of the first metal, and
optionally recovering the so-produced HCl; and [0127] optionally
heating the chloride of the second metal under conditions effective
for converting it into an oxide of the second metal, and optionally
recovering the so-produced HCl.
[0128] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0129] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0130] controlling the
concentration of HCl in the leachate and/or the temperature of the
leachate so as to precipitate the first metal in the form of a
chloride, and removing the precipitate from the leachate; [0131]
controlling the concentration of HCl in the leachate and/or the
temperature of the leachate so as to precipitate a second metal in
the form of a chloride, and removing the precipitate from the
leachate; [0132] optionally heating the chloride of the first metal
under conditions effective for converting it into an oxide of the
first metal, and optionally recovering the so-produced HCl; and
[0133] optionally heating the chloride of the second metal under
conditions effective for converting it into an oxide of the second
metal, and optionally recovering the so-produced HCl.
[0134] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0135] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0136] controlling the
concentration of HCl in the leachate and/or the temperature of the
leachate so as to precipitate the first metal in the form of a
chloride, and removing the precipitate from the leachate; [0137]
reacting the leachate with HCl so as to obtain a precipitate
comprising a second metal in the form of a chloride, and removing
the precipitate from the leachate, [0138] optionally heating the
chloride of the first metal under conditions effective for
converting it into an oxide of the first metal, and optionally
recovering the so-produced HCl; and [0139] optionally heating the
chloride of the second metal under conditions effective for
converting it into an oxide of the second metal, and optionally
recovering the so-produced HCl.
[0140] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0141] leaching
a material comprising a first metal with HCl so as to obtain a
leachate comprising ions of the first metal and a solid, and
separating the solid from the leachate; [0142] reacting the
leachate with HCl so as to obtain a precipitate comprising the
first metal in the form of a chloride, and removing the precipitate
from the leachate; [0143] controlling the concentration of HCl in
the leachate and/or the temperature of the leachate so as to
precipitate a second metal in the form of a chloride, and removing
the precipitate from the leachate; [0144] optionally heating the
chloride of the first metal under conditions effective for
converting it into an oxide of the first metal, and optionally
recovering the so-produced HCl; and [0145] optionally heating the
chloride of the second metal under conditions effective for
converting it into an oxide of the second metal, and optionally
recovering the so-produced HCl.
[0146] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0147] leaching
a material comprising magnesium and iron with HCl so as to obtain a
leachate comprising magnesium ions and iron ions and a solid, and
separating the solid from the leachate; [0148] reacting the
leachate with HCl so as to obtain a precipitate comprising
magnesium chloride, and removing the precipitate from the leachate
so as to obtain a liquid comprising iron chloride; [0149] treating
the liquid under conditions effective for converting the iron
chloride into iron oxide and optionally recovering HCl; and [0150]
optionally heating the magnesium chloride under conditions
effective for converting it into magnesium oxide, and optionally
recovering the so-produced HCl.
[0151] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0152] leaching
a material comprising magnesium and iron with HCl so as to obtain a
leachate comprising magnesium ions and iron ions and a solid, and
separating the solid from the leachate; [0153] controlling the
concentration of HCl in the leachate and/or the temperature of the
leachate so as to precipitate magnesium chloride, and removing the
precipitate from the leachate, thereby obtaining a liquid; [0154]
treating the liquid under conditions effective for converting the
iron chloride into iron oxide and optionally recovering HCl; and
[0155] optionally heating the magnesium chloride under conditions
effective for converting it into magnesium oxide, and optionally
recovering HCl.
[0156] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0157] leaching
a material comprising magnesium, aluminum and iron with HCl so as
to obtain a leachate comprising magnesium ions, aluminum ions and
iron ions and a solid, and separating the solid from the leachate;
[0158] controlling the concentration of HCl in the leachate and/or
the temperature of the leachate so as to precipitate magnesium
chloride, and removing the precipitate from the leachate, [0159]
reacting the leachate with HCl so as to obtain a precipitate
comprising aluminum chloride, and removing the precipitate from the
leachate so as to obtain a liquid comprising iron chloride; [0160]
optionally treating the liquid under conditions effective for
converting the iron chloride into iron oxide and optionally
recovering HCl; [0161] optionally heating the precipitate under
conditions effective for converting aluminum chloride into into
alumina and optionally recovering gaseous HCl so-produced; and
[0162] optionally heating the magnesium chloride under conditions
effective for converting it into magnesium oxide, and optionally
recovering HCl.
[0163] According to another aspect, there is provided a process for
preparing various products, the process comprising: [0164] leaching
a material comprising magnesium, aluminum and iron with HCl so as
to obtain a leachate comprising magnesium ions, aluminum ions and
iron ions and a solid, and separating the solid from the leachate;
[0165] reacting the leachate with HCl so as to obtain a precipitate
comprising aluminum chloride, and removing the precipitate from the
leachate; [0166] controlling the concentration of HCl in the
leachate and/or the temperature of the leachate so as to
precipitate magnesium chloride, and removing the precipitate from
the leachate so as to obtain a liquid comprising iron chloride
[0167] optionally treating the liquid under conditions effective
for converting the iron chloride into iron oxide and optionally
recovering HCl; [0168] optionally heating the precipitate under
conditions effective for converting aluminum chloride into into
alumina and optionally recovering gaseous HCl so-produced; and
[0169] optionally heating the magnesium chloride under conditions
effective for converting it into magnesium oxide, and optionally
recovering HCl.
BRIEF DESCRIPTION OF DRAWINGS
[0170] In the following drawings, which represent by way of example
only, various embodiments of the disclosure:
[0171] FIG. 1 shows a bloc diagram of an example of process for
preparing alumina and various other products according to the
present disclosure;
[0172] FIG. 2 is an extraction curve for Al and Fe in which the
extraction percentage is expressed as a function of a leaching time
in a process according to an example of the present
application;
[0173] FIG. 3 shows a bloc diagram of another example of process
for preparing alumina and various other products according to the
present disclosure;
[0174] FIG. 4 is a schematic representation of an example of a
process for purifying/concentrating HCl according to the present
disclosure;
[0175] FIG. 5 is a schematic representation of an example of a
process for purifying/concentrating HCl according to the present
disclosure;
[0176] FIG. 6 shows another bloc diagram of an example of process
for preparing alumina and various other products according to the
present disclosure;
[0177] FIG. 7 shows another bloc diagram of an example of process
for preparing alumina and various other products according to the
present disclosure;
[0178] FIG. 8 shows another bloc diagram of an example of process
for preparing various products
[0179] FIG. 9 shows another bloc diagram of an example of process
according to the present disclosure;
[0180] FIGS. 10A and 10B show further bloc diagrams of examples of
processes according to the present disclosure;
[0181] FIGS. 11A and 11B show a further bloc diagrams of examples
of processes according to the present disclosure; FIGS. 12A and 12B
show further bloc diagrams of examples of processes according to
the present disclosure;
[0182] FIG. 13 shows another bloc diagram of an example of process
for preparing alumina and various other products according to the
present disclosure;
[0183] FIG. 14 shows another bloc diagram of an example of process
for preparing alumina and various other products according to the
present disclosure;
[0184] FIG. 15 shows solubilisation curves of various metal
chlorides as a function of HCl concentration;
[0185] FIG. 16 shows solubilisation curves of MgCl.sub.2 at various
temperatures;
[0186] FIG. 17 shows solubilisation curves of various metal
chlorides as a function of HCl concentration; and
[0187] FIG. 18 shows a bloc diagram of an example of process for
preparing alumina and various other products according to the
present disclosure.
DETAILLED DESCRIPTION OF VARIOUS EMBODIMENTS
[0188] The following non-limiting examples further illustrate the
technology described in the present disclosure.
[0189] The aluminum-containing material can be for example chosen
from aluminum-containing ores (such as aluminosillicate minerals,
clays, argillite, nepheline, mudstone, beryl, cryolite, garnet,
spinel, bauxite, carbonatite, kyanite, kaolin, serpentine or
mixtures thereof can be used). The aluminum-containing material can
also be a recycled industrial aluminum-containing material such as
slag, red mud or fly ashes.
[0190] The expression "red mud" as used herein refers, for example,
to an industrial waste product generated during the production of
alumina. For example, such a waste product can comprise silica,
aluminum, iron, calcium, and optionally titanium. It can also
comprise an array of minor constituents such as Na, K, Cr, V, Ni,
Ba, Cu, Mn, Pb, and/or Zn etc. For example, red mud can comprises
about 15 to about 80% by weight of Fe.sub.2O.sub.3, about 1 to
about 35% by weight Al.sub.2O.sub.3, about 1 to about 65% by weight
of SiO.sub.2, about 1 to about 20% by weight of Na.sub.2O, about 1
to about 20% by weight of CaO, and from 0 to about 35% by weight of
TiO.sub.2. According to another example, red mud can comprise about
30 to about 65% by weight of Fe.sub.2O.sub.3, about 10 to about 20%
by weight Al.sub.2O.sub.3, about 3 to about 50% by weight of
SiO.sub.2, about 2 to about 10% by weight of Na.sub.2O, about 2 to
about 8% by weight of CaO, and from 0 to about 25% by weight of
TiO.sub.2.
[0191] The expression "fly ashes" as used herein refers, for
example, to an industrial waste product generated in combustion.
For example, such a waste product can contain various elements such
as silica, oxygen, aluminum, iron, calcium. For example, fly ashes
can comprise silicon dioxide (SiO.sub.2) and aluminium oxide
(Al.sub.2O.sub.3). For example, fly ashes can further comprises
calcium oxide (CaO) and/or iron oxide (Fe.sub.2O.sub.3). For
example fly ashes can comprise fine particles that rise with flue
gases. For example, fly ashes can be produced during combustion of
coal. For example, fly ashes can also comprise at least one element
chosen from arsenic, beryllium, boron, cadmium, chromium, chromium
VI, cobalt, lead, manganese, mercury, molybdenum, selenium,
strontium, thallium, and/or vanadium. For example, fly ashes can
also comprise rare earth elements and rare metals. For example, fly
ashes can be considered as an aluminum-containing material.
[0192] The expression "slag" as used herein refers, for example, to
an industrial waste product comprising aluminum oxide and
optionally other oxides such as oxides of calcium, magnesium, iron,
and/or silicon.
[0193] The expression "rare earth element" (also described as
"REE") as used herein refers, for example, to a rare element chosen
from scandium, yttrium, lanthanum, cerium, praseodymium, neodymium,
promethium, samarium, europium, gadolinium, terbium, dysprosium,
holmium, erbium, thulium, ytterbium, and lutetium. The expression
"rare metals" as used herein refers, for example, to rare metals
chosen from indium, zirconium, lithium, and gallium. These rare
earth elements and rare metals can be in various form such as the
elemental form (or metallic form), under the form of chlorides,
oxides, hydroxides etc. The expression "rare earths" as used in the
present disclosure as a synonym of "rare earth elements and rare
metals" that is described above.
[0194] The expression "at least one iron chloride" as used herein
refers to FeCl.sub.2, FeCl.sub.3 or a mixture thereof.
[0195] The term "hematite" as used herein refers, for example, to a
compound comprising .alpha.-Fe.sub.2O.sub.3,
.gamma.-Fe.sub.2O.sub.3, .beta.-FeO.OH or mixtures thereof.
[0196] The term "serpentine" as used herein refers, for example, to
an ore that comprises Mg and optionally iron. For example, the ore
can also comprise nickel, aluminum and/or cobalt. For example, the
serpentine can be chosen from antigorite, chrysotile and
lizardite.
[0197] The expression "iron ions" as used herein refers, for
example to ions comprising to at least one type of iron ion chosen
from all possible forms of Fe ions. For example, the at least one
type of iron ion can be Fe.sup.2+, Fe.sup.3+, or a mixture
thereof.
[0198] The expression "aluminum ions" as used herein refers, for
example to ions comprising to at least one type of aluminum ion
chosen from all possible forms of Al ions. For example, the at
least one type of aluminum ion can be Al.sup.3+.
[0199] The expression "at least one aluminum ion", as used herein
refers, for example, to at least one type of aluminum ion chosen
from all possible forms of Al ions. For example, the at least one
aluminum ion can be Al.sup.3+.
[0200] The expression "at least one iron ion", as used herein
refers, for example, to at least one type of iron ion chosen from
all possible forms of Fe ions. For example, the at least one iron
ion can be Fe.sup.2+, Fe.sup.3+, or a mixture thereof.
[0201] The expression "at least one precipitated iron ion", as used
herein refers, for example, to at least one type of iron ion chosen
from all possible forms of Fe ions that was precipitated in a solid
form. For example, the at least one iron ion present in such a
precipitate can be Fe.sup.2+, Fe.sup.3+, or a mixture thereof.
[0202] Terms of degree such as "about" and "approximately" as used
herein mean a reasonable amount of deviation of the modified term
such that the end result is not significantly changed. These terms
of degree should be construed as including a deviation of at least
.+-.5% or at least .+-.10% of the modified term if this deviation
would not negate the meaning of the word it modifies.
[0203] The expression "substantially selectively isolate" as used
herein when referring to isolating a compound refers, for example,
to isolating such a compound together with less than 30, 25, 20,
15, 10, 5, 3, 2 or 1% of impurities. Such impurities can be other
compounds such as other metals.
[0204] The expressions "substantially selectively precipitating",
"substantially selectively precipitate" and their equivalents as
used herein when referring to precipitating a compound refers, for
example, to precipitating such a compound together with less than
30, 25, 20, 15, 10, 5, 3, 2 or 1% of impurities. Such impurities
can be other compounds such as other metals.
[0205] For example, the material can be leached with HCl having a
concentration of about 10 to about 50 weight %, about 15 to about
45 weight %, of about 18 to about 45 weight % of about 18 to about
32 weight %, of about 20 to about 45 weight %, of about 25 to about
45 weight %, of about 26 to about 42 weight %, of about 28 to about
40 weight %, of about 30 to about 38 weight %, or between 25 and 36
weight %. For example, HCl at about 18 wt % or about 32 wt % can be
used.
[0206] Leaching can also be carried out by adding dry highly
concentrated acid (for example, 85%, 90% or 95%) in gas phase into
the aqueous solution. Alternatively, leaching can also be carried
out by using a weak acid solution (for example <3 wt %).
[0207] For example, leaching can be carried out by using HCl having
a concentration of about 18 to about 32 wt % in a first reactor and
then, by using HCl having concentration of about 90 to about 95%,
or about 95 to about 100% (gaseous) in a second reactor.
[0208] For example, leaching can be carried out by using HCl having
a concentration of about 18 to about 32 wt % in a first reactor
then, by using HCl having concentration of about 90 to about 95%
(gaseous) in a second reactor; and by using HCl having
concentration of about 90 to about 95% (gaseous) in a third
reactor.
[0209] For example, leaching can be carried out under an inert gas
atmosphere (for example argon or nitrogen).
[0210] For example, leaching can be carried out under an atmosphere
of NH.sub.3.
[0211] For example, the material can be leached at a temperature of
about 125 to about 225.degree. C., about 150 to about 200.degree.
C., about 160 to about 190.degree. C., about 185 to about
190.degree. C., about 160 to about 180.degree. C., about 160 to
about 175.degree. C., or about 165 to about 170.degree. C.
[0212] For example, the material can be leached at a pressure of
about 4 to about 10 barg, about 4 to about 8 barg, or about 5 to
about 6 barg.
[0213] For example a first leaching can be carried out at
atmospheric pressure and then, at least one further leaching (for
example 1, 2 or 3 subsequent leaching steps) can be carried out
under pressure.
[0214] For example, leaching can be a continuous leaching or
semi-continous.
[0215] For example, the material can be an aluminum-containing
material.
[0216] For example, the material can be an iron-containing
material.
[0217] For example, the material can be a zinc-containing
material.
[0218] For example, the material can be a copper-containing
material.
[0219] For example, the material can be a gold-containing
material.
[0220] For example, the material can be a silver-containing
material.
[0221] For example, the material can be a molybdenum-containing
material.
[0222] For example, the material can be a cobalt-containing
material.
[0223] For example, the material can be a magnesium-containing
material.
[0224] For example, the material can be a lithium-containing
material.
[0225] For example, the material can be a manganese-containing
material.
[0226] For example, the material can be a nickel-containing
material.
[0227] For example, the material can be a palladium-containing
material.
[0228] For example, the material can be a platinum-containing
material.
[0229] For example, the material can be a magnesium-containing
material.
[0230] For example, the material can be a lithium-containing
material.
[0231] For example, the material can be a thorium-containing
material.
[0232] For example, the material can be a phosphorus-containing
material.
[0233] For example, the material can be a an uranium-containing
material.
[0234] For example, the material can be a titanium-containing
material.
[0235] For example, the material can be a rare earth
elements-containing material.
[0236] For example, the material can be a rare metal-containing
material.
[0237] The processes of the present disclosure can be effective for
treating various materials. The at least one material can be an
aluminum-containing material, The aluminum-containing material can
be an aluminum-containing ore. For example, clays, argillite,
mudstone, beryl, cryolite, garnet, spinel, bauxite, serpentine or
mixtures thereof can be used as starting material. The
aluminum-containing material can also be a recycled industrial
aluminum-containing material such as slag. The aluminum-containing
material can also be red mud.
[0238] The at least one material can be a nickel-containing
material. The nickel-containing material can be a nickel-containing
ore.
[0239] The at least one material can be a zinc-containing material.
The zinc-containing material can be a zinc-containing ore.
[0240] The at least one material can be a copper-containing
material. The copper-containing material can be a copper-containing
ore.
[0241] The at least one material can be a titanium-containing
material. The titanium-containing material can be a
titanium-containing ore.
[0242] The at least one material can be a magnesium-containing
material. The magnesium-containing material can be a
magnesium-containing ore.
[0243] The processes of the present disclosure can be effective for
treating various nickel-containing ores. For example, niccolite,
kamacite, taenite, limonite, garnierite, laterite, pentlandite,
serpentine, or mixtures thereof can be used.
[0244] The processes of the present disclosure can be effective for
treating various zinc-containing ores. For example, smithsonite,
warikahnite, sphalerite, serpentine or mixtures thereof can be
used.
[0245] The processes of the present disclosure can be effective for
treating various copper-containing ores. For example,
copper-containing oxide ores, can be used. For example,
chalcopyrite, chalcocite, covellite, bornite, tetrahedrite,
malachite, azurite, cuprite, chrysocolla, or mixtures thereof can
also be used.
[0246] The processes of the present disclosure can be effective for
treating various titanium-containing ores. For example,
ecandrewsite, geikielite, pyrophanite, ilmenite, or mixtures
thereof can be used.
[0247] The processes of the present disclosure can be effective for
treating various magnesium-containing ores. For example, the
magnesium-containing ore can be chosen from serpentine, asbestos,
antigorite, chrysotile, lizardite, brucite, magnesite, dolomite,
kieserite, bischofite, langbeinite, epsomite, kainite, carnallite,
astrakanite, laterite, geikielite and polyhalite.
[0248] For example, in the processes, the leachate can be treated
with HCl that is in gaseous form.
[0249] For example, the processes can comprise reacting the
leachate with gaseous HCl so as to obtain the liquid and the
precipitate comprising the first metal under the form of a
chloride.
[0250] For example, the processes can comprise reacting the
leachate with dry gaseous HCl so as to obtain the liquid and the
precipitate comprising the first metal under the form of a
chloride.
[0251] For example, precipitating AlCl.sub.3 can comprise
crystallizing AlCl.sub.3.6H.sub.2O.
[0252] For example, the processes can comprise reacting the
leachate with acid of at least 30% wt. that was recovered,
regenerated and/or purified as indicated in the present disclosure
so as to obtain the liquid and the precipitate comprising the
aluminum ions in the form of AlCl.sub.3.6H.sub.2O.
[0253] For example, the processes can further comprise recycling
the gaseous HCl so-produced by contacting it with water so as to
obtain a composition having a concentration of about 18 to about 45
weight % or 25 to about 45 weight %.
[0254] For example, the processes can further comprise recycling
the gaseous HCl so-produced by contacting it with water so as to
obtain a composition having a concentration of about 18 to about 45
weight % or about 25 to about 45 weight % and using the composition
for leaching the material.
[0255] For example, the liquid can comprise iron chloride. Iron
chloride can comprise at least one of FeCl.sub.2, FeCl.sub.3, and a
mixture thereof.
[0256] For example, the liquid can have an iron chloride
concentration of at least 30% by weight; and can then be hydrolyzed
at a temperature of about 155 to about 350.degree. C.
[0257] For example, the liquid can be concentrated to a
concentrated liquid having an iron chloride concentration of at
least 30% by weight; and then the iron chloride can be hydrolyzed
at a temperature of about 155 to about 350.degree. C. while
maintaining a ferric chloride concentration at a level of at least
65% by weight, to generate a composition comprising a liquid and
precipitated hematite, and recovering the hematite.
[0258] For example, non-hydrolysable elements with hematite can be
concentrated back to a concentration of about 0.125 to about 52%
wt. in circulation loop in view of selective extraction.
[0259] For example, the liquid can be concentrated to a
concentrated liquid having a concentration of the at least one iron
chloride of at least 30% by weight; and then hydrolyzed at a
temperature of about 155 to about 350.degree. C.
[0260] For example, the liquid can be concentrated to a
concentrated liquid having a concentration of the at least one iron
chloride of at least 30% by weight; and then the at least one iron
chloride is hydrolyzed at a temperature of about 155 to about
350.degree. C. while maintaining a ferric chloride concentration at
a level of at least 65% by weight, to generate a composition
comprising a liquid and precipitated hematite, and recovering the
hematite.
[0261] For example, the liquid can be concentrated to a
concentrated liquid having a concentration of the at least one iron
chloride of at least 30% by weight; and then the at least one iron
chloride is hydrolyzed at a temperature of about 155 to about
350.degree. C. while maintaining a ferric chloride concentration at
a level of at least 65% by weight, to generate a composition
comprising a liquid and precipitated hematite; recovering the
hematite; and recovering rare earth elements and/or rare metals
from the liquid.
[0262] For example, the at least one iron chloride can be
hydrolyzed at a temperature of about, 150 to about 175, 160 to
about 175, 155 to about 170, 160 to about 170 or 165 to about
170.degree. C.
[0263] For example, the liquid can be concentrated to a
concentrated liquid having an iron chloride concentration of at
least 30% by weight; and then the iron chloride can be hydrolyzed
at a temperature of about 155 to about 350.degree. C. while
maintaining a ferric chloride concentration at a level of at least
65% by weight, to generate a composition comprising a liquid and
precipitated hematite; recovering the hematite; and recovering rare
earth elements and/or rare metals from the liquid.
[0264] For example, the processes can further comprise, after
recovery of the rare earth elements and/or rare metals, reacting
the liquid with HCl so as to cause precipitation of MgCl.sub.2, and
recovering same.
[0265] For example, the processes can further comprise calcining
MgCl.sub.2 into MgO.
[0266] For example, the processes can further comprises, after
recovery of the rare earth elements and/or rare metals, reacting
the liquid with HCl, and substantially selectively precipitating
Na.sub.2SO.sub.4. For example, Na.sub.2SO.sub.4 can be precipitated
by reacting the liquid with H.sub.2SO.sub.4.
[0267] For example, the processes can further comprises, after
recovery of the rare earth elements and/or rare metals, reacting
the liquid with HCl, and substantially selectively precipitating
K.sub.2SO.sub.4. For example, K.sub.2SO.sub.4 can be precipitated
by adding H.sub.2SO.sub.4.
[0268] For example, the liquid can be concentrated to a
concentrated liquid having an iron chloride concentration of at
least 30% by weight; and then the iron chloride can be hydrolyzed
at a temperature of about 155 to about 350.degree. C. while
maintaining a ferric chloride concentration at a level of at least
65% by weight, to generate a composition comprising a liquid and
precipitated hematite; recovering the hematite; and reacting the
liquid with HCl. For example, such processes can further comprises
reacting the liquid with H.sub.2SO.sub.4 so as to substantially
selectively precipitate Na.sub.2SO.sub.4. The processes can also
comprise further reacting the liquid with H.sub.2SO.sub.4 so as to
substantially selectively precipitating K.sub.2SO.sub.4.
[0269] For example, the processes can comprise reacting dry
individual salts (for example Na or K salts) obtained during the
processes with H.sub.2SO.sub.4 and recovering HCl while producing
marketable K.sub.2SO.sub.4 and Na.sub.2SO.sub.4 and recovering
hydrochloric acid of about 15 to about 90% wt.
[0270] For example, sodium chloride produced in the processes can
undergo a chemical reaction with sulfuric acid so as to obtain
sodium sulfate and regenerate hydrochloric acid. Potassium chloride
can undergo a chemical reaction with sulfuric acid so as to obtain
potassium sulfate and regenerate hydrochloric acid. Sodium and
potassium chloride brine solution can alternatively be the feed
material to adapted small chlor-alkali electrolysis cells. In this
latter case, common bases (NaOH and KOH) and bleach (NaOCl and
KOCl) are produced.
[0271] For example, the processes can further comprise, after
recovery of the rare earth elements and/or rare metals, recovering
NaCl from the liquid, reacting the NaCl with H.sub.2SO.sub.4, and
substantially selectively precipitating Na.sub.2SO.sub.4.
[0272] For example, the processes can further comprise, downstream
of recovery of the rare earth elements and/or rare metals,
recovering KCl from the liquid, reacting the KCl with
H.sub.2SO.sub.4, and substantially selectively precipitating
K.sub.2SO.sub.4.
[0273] For example, the processes can further comprise, downstream
of recovery of the rare earth elements and/or rare metals,
recovering NaCl from the liquid, carrying out an electrolysis to
generate NaOH and NaOCl.
[0274] For example, the processes can further comprise, downstream
of recovery of the rare earth elements and/or rare metals,
recovering KCl from the liquid, reacting the KCl, carrying out an
electrolysis to generate KOH and KOCl.
[0275] For example, the liquid can be concentrated to a
concentrated liquid having a concentration of the at least one iron
chloride of at least 30% by weight; and then the at least one iron
chloride is hydrolyzed at a temperature of about 155 to about
350.degree. C. while maintaining a ferric chloride concentration at
a level of at least 65% by weight, to generate a composition
comprising a liquid and precipitated hematite; recovering the
hematite; and extracting NaCl and/or KCl from the liquid.
[0276] For example, the processes can further comprise reacting the
NaCl with H.sub.2SO.sub.4 so as to substantially selectively
precipitate Na.sub.2SO.sub.4.
[0277] For example, the processes can further comprise reacting the
KCl with H.sub.2SO.sub.4 so as to substantially selectively
precipitate K.sub.2SO.sub.4.
[0278] For example, the processes can further comprise carrying out
an electrolysis of the NaCl to generate NaOH and NaOCl.
[0279] For example, the processes can further comprise carrying out
an electrolysis of the KCl to generate KOH and KOCl.
[0280] For example, the processes can comprise separating the solid
from the leachate and washing the solid so as to obtain silica
having a purity of at least 95%, at least 96%, at least 97%, at
least 98%, at least 99%, at least 99.5% or at least 99.9%.
[0281] For example, the processes can comprise reacting the
leachate with gaseous HCl so as to obtain the liquid and the
precipitate comprising the aluminum ions in the form of
AlCl.sub.3.6H.sub.2O.
[0282] For example, the processes can comprise reacting the
leachate with dry gaseous HCl so as to obtain the liquid and the
precipitate comprising the aluminum ions in the form of
AlCl.sub.3.6H.sub.2O.
[0283] For example, the processes can comprise reacting the
leachate with acid of at least 30% wt. that was recovered,
regenerated and/or purified as indicated in the present disclosure
so as to obtain the liquid and the precipitate comprising the
aluminum ions in the form of AlCl.sub.3.6H.sub.2O.
[0284] For example, the processes can comprise reacting the
leachate with gaseous HCl so as to obtain the liquid and the
precipitate comprising the aluminum ions, the precipitate being
formed by crystallization of AlCl.sub.3.6H.sub.2O.
[0285] For example, the processes can comprise reacting the
leachate with dry gaseous HCl so as to obtain the liquid and the
precipitate comprising the aluminum ions, the precipitate being
formed by crystallization of AlCl.sub.3.6H.sub.2O.
[0286] For example, aluminum ions can be precipitated under the
form of AlCl.sub.3 (for example AlCl.sub.3.6H.sub.2O) in a
crystallizer, for example, by adding HCl having a concentration of
about 26 to about 32 wt %.
[0287] For example, the gaseous HCl can have a HCl concentration of
at least 85% wt. or at least 90% wt.
[0288] For example, the gaseous HCl can have a HCl concentration of
about 90% wt., about 90% to about 95% wt., or about 90% to about
99% wt.
[0289] For example, during the crystallization of
AlCl.sub.3.6H.sub.2O, the liquid can be maintained at a
concentration of HCl of about 25 to about 35% by weight or about 30
to about 32% by weight.
[0290] For example, the crystallization can be carried out at a
temperature of about 45 to about 65.degree. C. or about 50 to about
60.degree. C.
[0291] For example, the HCl can be obtained from the gaseous HCl
so-produced.
[0292] For example, in the processes of the present disclosure, a
given batch or quantity of the material will be leached, will then
be converted into AlCl.sub.3 and when the HCl generated during
calcination of AlCl.sub.3 into Al.sub.2O.sub.3 will be used for
example to leach another given batch or quantity of the
material.
[0293] For example, the processes can comprise heating the
precipitate at a temperature of at least 180, 230, 250, 300, 350,
400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 925, 930,
1000, 1100, 1200 or 1250.degree. C. for converting AlCl.sub.3 or
Al(OH).sub.3 into Al.sub.2O.sub.3.
[0294] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise calcination of AlCl.sub.3.
[0295] For example, calcination is effective for converting
AlCl.sub.3 into beta-Al.sub.2O.sub.3.
[0296] For example, calcination is effective for converting
AlCl.sub.3 into alpha-Al.sub.2O.sub.3.
[0297] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination via a two-stage circulating
fluid bed reactor.
[0298] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination via a two-stage circulating
fluid bed reactor that comprises a preheating system.
[0299] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination at low temperature, for
example, about 300 to about 600.degree. C., about 325 to about
550.degree. C., about 350 to about 500.degree. C., about 375 to
about 450.degree. C., about 375 to about 425.degree. C., or about
385 to about 400.degree. C. and/or injecting steam.
[0300] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination at low temperature, for
example, at least 180.degree. C., at least 250.degree. C., at least
300.degree. C., at least 350.degree. C. and/or injecting steam.
[0301] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination at low temperature, for
example, less than 600.degree. C. and/or injecting steam.
[0302] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination by using coal as combustion
source and by using a degasification unit.
[0303] For example, steam (or water vapor) can be injected at a
pressure of about 200 to about 700 psig, about 300 to about 700
psig, about 400 to about 700 psig, about 550 to about 650 psig,
about 575 to about 625 psig, or about 590 to about 610 psig.
[0304] For example, steam (or water vapor) can be injected and a
plasma torch can be used for carrying fluidization.
[0305] For example, the steam (or water vapor) can be
overheated.
[0306] For example, the steam (or water vapor) can be at a
temperature of about 300 to about 400.degree. C.
[0307] For example, acid from the offgases generated during
calcination can be then treated via a gas phase purification
process.
[0308] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination by means of carbon monoxide
(CO).
[0309] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a calcination by means of a Refinery Fuel Gas
(RFG).
[0310] For example, calcination can be carried out by injecting
water vapor or steam and/or by using a combustion source chosen
from fossil fuels, carbon monoxide, a Refinery Fuel Gas, coal, or
chlorinated gases and/or solvents.
[0311] For example, calcination can be carried out by injecting
water vapor or steam and/or by using a combustion source chosen
from natural gas or propane.
[0312] For example, calcination can be carried out by providing
heat by means of electric heating, gas heating, microwave
heating.
[0313] The obtained alumina can be washed by demineralized water so
as to at least partially remove NaCl and/or KCl.
[0314] For example, the fluid bed reactor can comprise a metal
catalyst chosen from metal chlorides.
[0315] For example, thee fluid bed reactor can comprise a metal
catalyst that is FeCl.sub.3, FeCl.sub.2 or a mixture thereof.
[0316] For example, the fluid bed reactor can comprise a metal
catalyst that is FeCl.sub.3.
[0317] For example, the preheating system can comprise a plasma
torch.
[0318] For example, steam can be used as the fluidization medium
heating. Heating can also be electrical.
[0319] For example, a plasma torch can be used for preheating the
calcination reactor.
[0320] For example, a plasma torch can be used for preheating air
entering in the calcination reactor.
[0321] For example, a plasma torch can be used for preheating a
fluid bed.
[0322] For example, the calcination medium can be substantially
neutral in terms of O.sub.2 (or oxidation). For example, the
calcination medium can favorize reduction (for example a
concentration of CO of about 100 ppm).
[0323] For example, the calcination medium is effective for
preventing formation of Cl.sub.2.
[0324] For example, the processes can comprise converting
AlCl.sub.3.6H.sub.2O into Al.sub.2O.sub.3 by carrying out a
calcination of AlCl.sub.3.6H.sub.2O that is provided by the
combustion of gas mixture that comprises: [0325] CH.sub.4: 0 to
about 1% vol; [0326] C.sub.2H.sub.6: 0 to about 2% vol; [0327]
C.sub.3H.sub.8: 0 to about 2% vol; [0328] C.sub.4H.sub.10: 0 to
about 1% vol; [0329] N.sub.2: 0 to about 0.5% vol; [0330] H.sub.2:
about 0.25 to about 15.1% vol; [0331] CO: about 70 to about 82.5%
vol; and [0332] CO.sub.2: about 1.0 to about 3.5% vol.
[0333] Such a mixture can be efficient for reduction in off gas
volume of 15.3 to 16.3%; therefore the capacity increases of 15.3
to 16.3% proven on practical operation of the circulating fluid
bed. Thus for a same flow it represents an Opex of
0.65*16.3%=10.6%.
[0334] For example, the air to natural gas ratio of (Nm.sup.3/h
over Nm.sup.3/h) in the fluid bed can be about 9.5 to about 10
[0335] For example, the air to CO gas ratio of (Nm.sup.3/h over
Nm.sup.3/h) in the fluid bed can be about 2 to about 3.
[0336] For example, the processes can comprise, before leaching the
material, a pre-leaching removal of fluorine optionally contained
in the material.
[0337] For example, the processes can comprise leaching of the
material with HCl so as to obtain the leachate comprising aluminum
ions and the solid, separating the solid from the leachate; and
further treating the solid so as to separate SiO.sub.2 from
TiO.sub.2 that are contained therein.
[0338] For example, the processes can comprise leaching the
material with HCl so as to obtain the leachate comprising aluminum
ions and the solid, separating the solid from the leachate; and
further treating the solid with HCl so as to separate Si from Ti
that are contained therein.
[0339] For example, the processes can comprise leaching the
material with HCl so as to obtain the leachate comprising aluminum
ions and the solid, separating the solid from the leachate; and
further treating the solid with HCl at a concentration of less than
20% wt., at a temperature of less than 85.degree. C., in the
presence of MgCl.sub.2, so as to separate Si from Ti that are
contained therein.
[0340] For example, converting AlCl.sub.3 into Al.sub.2O.sub.3 can
comprise carrying out a one-step calcination.
[0341] For example, calcination can be carried out at different
temperatures with steam. Temperature applied of superheated steam
can be of about 350.degree. C. to about 550.degree. C. or about
350.degree. C. to about 940.degree. C. or about 350.degree. C. to
about 1200.degree. C.
[0342] For example, multi stage evaporation step of the hydrolyser
can be carried out to reduce drastically energy consumption.
[0343] For example, the processes can be effective for providing an
Al.sub.2O.sub.3 recovery yield of at least 93%, at least 94%, at
least 95%, about 90 to about 95%, about 92 to about 95%, or about
93 to about 95%.
[0344] For example, the processes can be effective for providing a
Fe.sub.2O.sub.3 recovery yield of at least 98%, at least 99%, about
98 to about 99.5%, or about 98.5 to about 99.5%.
[0345] For example, the processes can be effective for providing a
MgO recovery yield of at least 96%, at least 97%, at least 98%, or
about 96 to about 98%.
[0346] For example, the processes can be effective for providing a
HCl recovery yield of at least 98%, at least 99%, or about 98 to
about 99.9%.
[0347] For example, the processes can be effective for providing
chlorides of rare earth elements (REE-Cl) and chlorides of rare
metals (RM-Cl) in recovery yields of about 75% to about 96.5% by
using internal processes via an internal concentration loop.
[0348] For example, the processes can be effective for providing
hydrochloric acid recovery yield of about 99.75% with
non-hydrolysable elements.
[0349] For example, the material can be argillite.
[0350] For example, the material can be bauxite.
[0351] For example, the material can be red mud.
[0352] For example, the material can be fly ashes.
[0353] For example, the material can be chosen from industrial
refractory materials.
[0354] For example, the material chosen from aluminosilicate
minerals.
[0355] For example, the processes can be effective for avoiding
producing red mud.
[0356] For example, the alumina and the other products are
substantially free of red mud.
[0357] For example, HCl can be recycled. For example, such a
recycled HCl can be concentrated and/or purified.
[0358] For example, gaseous HCl can be concentrated and/or purified
by means of H.sub.2SO.sub.4. For example, gaseous HCl can be passed
through a packed column where it is contacted with a
H.sub.2SO.sub.4 countercurrent flow. For example, by doing so,
concentration of HCl can be increased by at least 50% wt., at least
60% wt., at least 70% wt., at least 75% wt., at least 80% wt.,
about 50% wt. to about 80% wt., about 55% wt. to about 75% wt., or
about 60% wt. For example, the column can be packed with a polymer
such as polypropylene (PP) or polytrimethylene terephthalate
(PTT).
[0359] For example, gaseous HCl can be concentrated and/or purified
by means of CaCl.sub.2 or LiCl. For example, gaseous HCl can be
passed through a column packed with CaCl.sub.2 or LiCl.
[0360] For example, AlCl.sub.3.6H.sub.2O obtained in the processes
of the present disclosure can be further purified as descriobed in
U.S. 61/726,079, that is hereby incorporated by reference in its
entirety.
[0361] For example, MgCl.sub.2 can be substantially selectively
precipitated from the leachate and removed therefrom and then, the
leachate can be reacted with HCl so as to obtain the liquid and the
precipitate comprising the aluminum ions in the form of AlCl.sub.3,
and separating the precipitate from the liquid.
[0362] For example, the leachate can be reacted with HCl so as to
obtain the liquid and the precipitate comprising the aluminum ions
in the form of AlCl.sub.3, and separating the precipitate from the
liquid, and then the MgCl.sub.2 is substantially selectively
precipitated from the leachate and removed therefrom.
[0363] For example, the aluminum-containing material can beleached
with HCl so as to obtain the leachate comprising aluminum ions,
magnesium ions and the solid, and the solid is separated from the
leachate at a temperature of at least 50, 60, 75 or 100.degree. C.
For example, a filtration can be carried out and the temperature of
the leachate can have a value as previously indicated.
[0364] For example, MgCl.sub.2 can be substantially selectively
precipitated from the leachate at a temperature of about 5 to about
70.degree. C., about 10 to about 60.degree. C., about 10 to about
40.degree. C., or about 15 to about 30.degree. C.
[0365] For example, the processes can comprise, before reacting the
leachate with HCl so as to obtain the liquid and the precipitate,
controlling the temperature of the leachate so as to substantially
selectively precipitate a second metal in the form of a chloride,
and removing the precipitate from the leachate.
[0366] For example, the processes can comprise, after reacting the
leachate with HCl so as to obtain the liquid and the precipitate,
controlling the temperature of the leachate so as to substantially
selectively precipitate a second metal in the form of a chloride,
and removing the precipitate from the leachate.
[0367] For example, the processes can further comprises treating
the precipitate under conditions effective for converting the
chloride of the first metal it into an oxide of the first metal and
optionally recovering gaseous HCl so-produced.
[0368] For example, the processes can further comprises treating
the precipitate under conditions effective for converting the
chloride of the second metal it into an oxide of the second metal
and optionally recovering gaseous HCl so-produced.
[0369] For example, the solid can be treated with HCl and the metal
chloride so as to obtain a liquid portion comprising Ti and a solid
portion containing Si and wherein the liquid portion is separated
from the solid portion.
[0370] For example, the solid can be treated with HCl and the metal
chloride so as to obtain a liquid portion comprising
TiCl.sub.4.
[0371] For example, the process can further comprise converting
TiCl.sub.4 into TiO.sub.2.
[0372] For example, TiCl.sub.4 can be converted into TiO.sub.2 by
solvent extraction of the third liquid fraction and subsequent
formation of titanium dioxide from the solvent extraction.
[0373] For example, TiCl.sub.4 can be reacted with water and/or a
base to cause precipitation of TiO.sub.2.
[0374] For example, TiCl.sub.4 can be converted into TiO.sub.2 by
means of a pyrohydrolysis, thereby generating HCl.
[0375] For example, TiCl.sub.4 can be converted into TiO.sub.2 by
means of a pyrohydrolysis, thereby generating HCl that is
recycled.
[0376] For example, the metal chloride can be MgCl.sub.2 or
ZnCl.sub.2.
[0377] For example, the solid can comprise TiO.sub.2 and SiO.sub.2
and the solid is treated with Cl.sub.2 and carbon in order to
obtain a liquid portion and a solid portion, and wherein the solid
portion and the liquid portion are separated from one another.
[0378] For example, the liquid portion can comprise TiCl.sub.2
and/or TiCl.sub.4.
[0379] For example, the liquid portion can comprise TiCl.sub.4.
[0380] For example, the process can further comprise heating
TiCl.sub.4 so as to convert it into TiO.sub.2.
[0381] For example, the obtained TiO.sub.2 can be purified by means
of a plasma torch.
[0382] For example, the various products obtained by the processes
of the present disclosure such as alumina, hematite, titanium
oxides, magnesium oxides, rare earth elements and rare metals can
be further purified by means of a plasma torch. For example, the
rare earth elements and rare metals, once isolated, can be
individually injected into a plasma torch so as to further purify
them.
[0383] For example, the processes can further comprise converting
alumina (Al.sub.2O.sub.3) into aluminum. Conversion of alumina into
aluminum can be carried out, for example, by using the Hall-Heroult
process. References is made to such a well known process in various
patents and patent applications such as US 20100065435; US
20020056650; U.S. Pat. No. 5,876,584; U.S. Pat. No. 6,565,733.
Conversion can also be carried out by means of other methods such
as those described in U.S. Pat. No. 7,867,373; U.S. Pat. No.
4,265,716; U.S. Pat. No. 6,565,733 (converting alumina into
aluminum sulfide followed by the conversion of aluminum sulfide
into aluminum.). For example, aluminium can be produced by using a
reduction environment and carbon at temperature below 200.degree.
C. Aluminum can also be produced by reduction using potassium and
anhydrous aluminum chloride (Wohler Process).
[0384] For example, controlling the temperature of the leachate so
as to precipitate the the first metal in the form of a chloride,
and removing the precipitate from the leachate, can be carried out
before reacting the leachate with HCl so as to obtain a liquid and
a precipitate comprising a chloride of the second metal, and
separating the precipitate from the liquid.
[0385] For example, controlling the temperature of the leachate so
as to precipitate the the first metal in the form of a chloride,
and removing the precipitate from the leachate, can be carried out
after reacting the leachate with HCl so as to obtain a liquid and a
precipitate comprising a chloride of the second metal, and
separating the precipitate from the liquid.
[0386] For example, reacting the leachate with HCl so as to obtain
a precipitate comprising the first metal in the form of a chloride,
can be carried out by substantially selectively precipitating the
first metal chloride.
[0387] For example, reacting the leachate with HCl so as to obtain
a precipitate comprising the second metal in the form of a
chloride, can be carried out by substantially selectively
precipitating the second metal chloride,
[0388] For example, controlling the temperature of the leachate so
as to precipitate the the first metal in the form of a chloride can
be carried out substantially selectively.
[0389] For example, controlling the temperature of the leachate so
as to precipitate the second metal in the form of a chloride can be
carried out substantially selectively.
[0390] For example, controlling the concentration of HCl in the
leachate and/or the temperature of the leachate so as to
precipitate the first metal in the form of a chloride, can be
carried out substantially selectively.
[0391] For example, controlling the concentration of HCl in the
leachate and/or the temperature of the leachate so as to
precipitate the second metal in the form of a chloride, can be
carried out substantially selectively.
[0392] For example, the first metal can chosen from aluminum, iron,
zinc, copper, gold, silver, molybdenum, cobalt, magnesium, lithium,
manganese, nickel, palladium, platinum, thorium, phosphorus,
uranium and titanium, and/or at least one rare earth element and/or
at least one rare metal
[0393] For example, the liquid can comprise a second metal.
[0394] For example, the second metal can be chosen from aluminum,
iron, zinc, copper, gold, silver, molybdenum, cobalt, magnesium,
lithium, manganese, nickel, palladium, platinum, thorium,
phosphorus, uranium and titanium, and/or at least one rare earth
element and/or at least one rare metal
[0395] For example, the process can comprise separating the
precipitate from the liquid and heating the second metal in order
to convert a chloride of the second metal into an oxide of the
second metal.
[0396] For example, the second metal can be magnesium.
[0397] For example, the second metal can be aluminum.
[0398] For example, the first metal can be aluminum and the second
metal can be magnesium.
[0399] For example, the second metal can be aluminum and the first
metal can be magnesium.
[0400] For example, the processes can comprise:
[0401] separating the solid from the leachate;
[0402] leaching the solid with an acid so as to obtain another
leachate; and
[0403] recovering a third metal from the another leachate.
[0404] For example, the third metal can be chosen from aluminum,
iron, zinc, copper, gold, silver, molybdenum, cobalt, magnesium,
lithium, manganese, nickel, palladium, platinum, thorium,
phosphorus, uranium and titanium, and/or at least one rare earth
element and/or at least one rare metal.
[0405] For example, the third metal can be titanium.
[0406] For example, the acid can be chosen from HCl, HNO.sub.3,
H.sub.2SO.sub.4 and mixtures thereof.
[0407] For example, the process can comprise recovering the third
metal from the another leachate by precipitating the third
metal.
[0408] For example, the third metal can be precipitated by reacting
it with HCl.
[0409] For example, the process can further comprise heating the
third metal in order to convert a chloride of the third metal into
an oxide of the third metal.
[0410] For example, the first metal can be magnesium.
[0411] For example, the first metal can be nickel.
[0412] For example, the second metal can be magnesium.
[0413] For example, the second metal can be nickel.
[0414] For example, the process can comprise reacting the leachate
with gaseous HCl so as to obtain a liquid and a precipitate
comprising MgCl.sub.2.
[0415] For example, the process comprises reacting the leachate
with gaseous HCl so as to obtain a liquid and a precipitate
comprising MgCl.sub.2.
[0416] For example, NaCl recovered from the processes of the
present disclosure can be reacted with SO.sub.2, so as to produce
HCl and Na.sub.2SO.sub.4. Such a reaction that is an exothermic
reaction can generate steam that can be used to activate a turbine
and eventually produce electricity.
[0417] For example, U and/or Th can be tretaed with the processes
of the present disclosure. For example, these two elements can be
in such processes in admixtures with iron ions and they can be
separated therefrom by means of at least one ion exchange
resin.
[0418] For example, the processes can comprise substantially
selectively precipitating the magnesium ions by reacting the
leachate with the precipitating agent.
[0419] For example, the precipitating agent can be
Mg(OH).sub.2.
[0420] For example, the at least one metal can be nickel.
[0421] For example, the at least one metal can be cobalt.
[0422] For example, the at least one metal can be iron.
[0423] For example, the at least one metal can be aluminum.
[0424] In the processes of the present disclosure, when the
material to be treated comprises aluminum and magnesium, magnesium
can be first removed from the leachate by controlling temperature
of said leachate so as to substantially selectively cause
precipitation (or crystallization) of MgCl.sub.2, remove it from
the leachate and then substantially selectively cause precipitation
of AlCl.sub.3 by reacting the leachate with HCl (for example
gaseous HCl). Alternatively, the leachate can be reacted with HCl
to substantially selectively cause precipitation (or
crystallization) of AlCl.sub.3 (for example gaseous HCl). In such a
case the temperature can be maintained for example above 50, 60,
70, 80, or 90.degree. C. AlCl.sub.3 is then removed from the
leachate and then, temperature of the leachate is controlled so as
to substantially selectively cause precipitation of MgCl.sub.2.
Depending on the concentration of Al vs Mg in the starting material
one scenario or the other can be selected. For example, if the
concentration of Mg is greater than the concentration of Al, Mg can
be removed first from the leachate. For example, if the
concentration of Al is greater than the concentration of Mg, Al can
be removed first from the leachate.
[0425] In the processes of the present disclosure, when the
material to be treated comprises aluminum, iron and magnesium.
Magnesium can be first removed from the leachate by controlling
temperature of said leachate so as to substantially selectively
cause precipitation (or crystallization) of MgCl.sub.2, remove it
from the leachate and then substantially selectively cause
precipitation of AlCl.sub.3 by reacting the leachate with HCl (for
example gaseous HCl). Then, the remaining composition comprising
iron chloride can be treated so as to convert iron chloride into
iron oxide by using one of the methods discussed in the present
disclosure. Alternatively, the leachate can be reacted with HCl to
substantially selectively cause precipitation (or crystallization)
of AlCl.sub.3 (for example gaseous HCl). In such a case the
temperature can be maintained for example above 50, 60, 70, 80, or
90.degree. C. AlCl.sub.3 is then removed from the leachate and
then, temperature of the leachate is controlled so as to
substantially selectively cause precipitation of MgCl.sub.2. Then,
the remaining composition comprising iron chloride can be treated
so as to convert iron chloride into iron oxide by using the methods
discussed in the present disclosure.
[0426] For example, the precipitate can be reacted with a base (for
example KOH or NaOH). For example, AlCl.sub.3 can be converted into
Al(OH).sub.3 before calcination.
[0427] According to one example as shown in FIG. 1, the processes
can involve the following steps (the reference numbers in FIG. 1
correspond to the following steps):
[0428] 1--The aluminum-containing material is reduced to an average
particle size of about 50 to about 80 .mu.m.
[0429] 2--The reduced and classified material is treated with
hydrochloric acid which allows for dissolving, under a
predetermined temperature and pressure, the aluminum with other
elements like iron, magnesium and other metals including rare earth
elements and/or rare metals. The silica and titanium (if present in
raw material) remain totally undissolved.
[0430] 3--The mother liquor from the leaching step then undergoes a
separation, a cleaning stage in order to separate the solid from
the metal chloride in solution.
[0431] 4--The spent acid (leachate) obtained from step 3 is then
brought up in concentration with dry and highly concentrated
gaseous hydrogen chloride by sparging this one into a crystallizer.
This results into the crystallization of aluminum chloride
hexahydrate (precipitate) with a minimum of other impurities.
Depending on the concentration of iron chloride at this stage,
further crystallization step(s) can be required. The precipitate is
then separated from the liquid. For example, particle size of
crystals can be about 100 to about 500 microns, about 200 to about
400 microns, or about 200 to about 300 microns. Alternatively,
particle size of crystals can be about 100 to about 200 microns,
about 300 to about 400 microns or about 400 to 500 microns.
[0432] 5--The aluminum chloride hexahydrate is then calcined (for
example by means of a rotary kiln, fluid bed, etc) at high
temperature in order to obtain the alumina form. Highly
concentrated gaseous hydrogen chloride is then recovered and excess
is brought in aqueous form to the highest concentration possible so
as to be used (recycled) in the acid leaching step. Acid can also
be directly sent in gas phase to the acid purification stage to
increase HCl concentration from about 30 wt % to about 95 wt %.
This can be done, for example, during drying stage.
[0433] 6--Iron chloride (the liquid obtained from step 4) is then
pre-concentrated and hydrolyzed at low temperature in view of the
Fe.sub.2O.sub.3 (hematite form) extraction and acid recovery from
its hydrolysis. All heat recovery from the calcination step (step
5), the leaching part exothermic reaction (step 1) and other
section of the processes is being recovered into the
pre-concentrator.
[0434] 10--After the removal of hematite, a solution rich in rare
earth elements and/or rare metals can be processed. As it can be
seen in FIG. 3, an internal recirculation can be done (after the
removal of hematite) and the solution rich in rare earth elements
and/or rare metals can be used for crystallization stage 4.
Extraction of the rare earth elements and/or rare metals can be
done as described in WO/2012/126092 and/or WO/2012/149642. These
two documents are hereby integrated by reference in their
entirety.
[0435] Other non-hydrolysable metal chlorides (Me-Cl) such as
MgCl.sub.2 and others then undergo the following steps:
[0436] 7--The solution rich in magnesium chloride and other
non-hydrolysable products at low temperature is then brought up in
concentration with dry and highly concentrated gaseous hydrogen
chloride by sparging it into a crystallizer. This results into the
precipitation of magnesium chloride as an hexahydrate, for example
after sodium and potassium chloride removal.
[0437] 8--Magnesium chloride hexahydrate is then calcined (either
through a rotary kiln, fluid bed, etc.) and hydrochloric acid at
very high concentration is thus regenerated and brought back to the
leaching step.
[0438] 9--Other Me-Cl undergo a standard pyrohydrolysis step where
mixed oxides (Me-O) can be produced and hydrochloric acid at the
azeotropic point (20.2% wt.) is regenerated.
[0439] 13--Ti contained in the solid obtained from step 3 can be
treated so as to separate Si from Ti and thus obtain SiO.sub.2 and
TiO.sub.2.
[0440] NaCl produced in this process can undergo chemical reaction
with H.sub.2SO.sub.4 to produce Na.sub.2SO.sub.4 and HCl at a
concentration at or above azeotropic concentration. Moreover, KCl
can undergo chemical reaction with H.sub.2SO.sub.4 to produce
K.sub.2SO.sub.4 and HCl having a concentration that is above the
azeotropic concentration. Sodium and potassium chloride brine
solution can be the feed material to adapted small chlor-alkali
electrolysis cells. In this latter case, common bases (NaOH and
KOH) and bleach (NaOCl and KOCl) are produced as well as HCl.
[0441] For example, the liquid can be concentrated to a
concentrated liquid having an iron chloride concentration of at
least 30% by weight; and then the iron chloride can be hydrolyzed
at a temperature of about 155 to about 350.degree. C. while
maintaining a ferric chloride concentration at a level of at least
65% by weight, to generate a composition comprising a liquid and
precipitated hematite, and recovering the hematite.
[0442] For example, the liquid can be concentrated to a
concentrated liquid having an iron chloride concentration of at
least 30% by weight; and then the iron chloride can be hydrolyzed
at a temperature of about 155 to about 350.degree. C. while
maintaining a ferric chloride concentration at a level of at least
65% by weight, to generate a composition comprising a liquid and
precipitated hematite; recovering the hematite; and recovering rare
earth elements and/or rare metals from the liquid. For example, the
process can further comprise, after recovery of the rare earth
elements and/or rare metals, reacting the liquid with HCl so as to
cause precipitation of MgCl.sub.2, and recovering same.
[0443] As previously indicated, various aluminum-containing
materials can be used as starting material of the processes
disclosed in the present disclosure. Examples with clays and
bauxite have been carried out. However, the person skilled in the
art will understand that the continuous processes can handle high
percentages of silica (>55%) and impurities as well as
relatively low percentages of aluminum (for example as low as about
15%) and still being economically and technically viable.
Satisfactory yields can be obtained (>93-95%) on Al.sub.2O.sub.3
and greater than 75%, 85 or 90% on rare earth elements and/or rare
metals. No pre-thermal treatment in most cases are required. The
processes disclosed in the present disclosure involve special
techniques on leaching and acid recovery at very high strength,
thereby offering several advantages over alkaline processes.
[0444] In step 1 the mineral, whether or not thermally treated is
crushed, milled, dried and classified to have an average particle
size of about 50 to about 80 .mu.m.
[0445] In step 2, the milled raw material is introduced into the
reactor and will undergo the leaching phase.
[0446] The leaching hydrochloric acid used in step 2 can be a
recycled or regenerated acid from steps 5, 6, 8, 9, 10 and 11 (see
FIG. 3) its concentration can vary from 15% to 45% weight. percent.
Higher concentration can be obtained using membrane separation,
cryogenic and/or high pressure approach. The acid leaching can be
carried out under pressure and at temperature close to its boiling
point thus, allowing a minimal digestion time and extended reaction
extent (90%-100%). Leaching (step 2) can be accomplished in a
semi-continuous mode where spent acid with residual free
hydrochloric acid is replaced by highly concentrated acid at a
certain stage of the reaction or allowing a reduced acid/mineral
ratio, thereby reducing reaction time and improving reaction
kinetics. For example, kinetic constant k can be: 0.5-0.75 g/moleL.
For example, leaching can be continuous leaching.
[0447] As previously indicated, alkali metals, iron, magnesium,
sodium, calcium, potassium, rare earth elements and other elements
will also be in a chloride form at different stages. Silica and
optionally titanium can remain undissolved and will undergo (step
3) a liquid/solid separation and cleaning stage. The processes of
the present disclosure tend to recover maximum amount of free
hydrochloric acid left and chlorides in solution in order to
maximize hydrochloric acid recovery yield, using techniques such as
rake classifying, filtration with band filters, centrifugation,
high pressure, rotofilters and others. Thanks to step 13, Ti
contained in the solid obtained from step 3 can be treated so as to
separate Si from Ti and thus obtain SiO.sub.2 and TiO.sub.2.
Various possible strategies can be used to separated Si from Ti as
previously indicated. For example, the solid can be further leached
(for example with HCl in the presence of a metal chloride (for
example MgCl.sub.2 or ZnCl.sub.2) so as to solubilize Ti (for
example in the form of TiCl.sub.4) while the Si remains solid.
Alternatively, the solid can be reacted with Cl.sub.2 (see FIGS.
10A and 10B). he purified silica can then optionally undergo one or
two additional leaching stages (for example at a temperature of
about 150 to about 160.degree. C.) so as to increase the purity of
silica above 99.9%.
[0448] Pure SiO.sub.2 (one additional leaching stage) cleaning with
nano water purity 99% min. Mother liquor free of silica is then
named as spent acid (various metal chlorides and water) and goes to
the crystallization step (step 4). Free HCl and chlorides recovery
can be at least 99, 99.5 or 99.9%
[0449] In step 4, the spent acid (or leachate) with a substantial
amount of aluminum chloride is then saturated with dry and highly
concentrated gaseous hydrogen chloride obtained or recycled from
step 5 or with aqueous HCl>30% wt., which results in the
precipitate of aluminum chloride hexahydrate
(AlCl.sub.3.6H.sub.2O). The precipitate retained is then washed and
filtered or centrifuged before being fed to the calcination stage
(step 5). The remaining of the spent acid from step 4 is then
processed to acid recovery system (steps 6 to 8) where pure
secondary products will be obtained.
[0450] In step 5, aluminum oxide (alumina) is directly obtained
from high temperature conditions. The highly concentrated hydrogen
chloride in gaseous form obtained can be fed to steps 4 and 7 for
crystallization where it can be treated through hydrophobic
membranes. The excess hydrogen chloride is absorbed and used as
regenerated acid to the leaching step 2 as highly concentrated
acid, higher than the concentration at the azeotropic point
(>20.2%). For example, such a concentration can be about 18 to
about 45 weight %, about 25 to about 45 weight % or between 25 and
36 weight %. Acid can also be redirected in gas phase directly
(>30 wt %) to acid purification.
[0451] After step 4, various chlorides derivatives (mainly iron
with magnesium and rare earth elements and rare metals) are next
subjected to an iron extraction step. Such a step can be carried
out for example by using the technology disclosed in WO
2009/153321, which is hereby incorporated by reference in its
entirety. Moreover, hematite can be seeded for crystal growth. For
example, hematite seeding can comprise recirculating the
seeding.
[0452] In step 6, a hydrolysis at low temperature (155-350.degree.
C.) is carried out and pure Fe.sub.2O.sub.3 (hematite) is being
produced and hydrochloric acid of at least 15% concentration is
being regenerated. The method as described in WO 2009/153321 is
processing the solution of ferrous chloride and ferric chloride,
possible mixtures thereof, and free hydrochloric acid through a
series of steps pre-concentration step, oxidation step where
ferrous chloride is oxidized into ferric form, and finally through
an hydrolysis step into an operational unit called hydrolyser where
the ferric chloride concentration is maintained at 65 weight % to
generate a rich gas stream where concentration ensures a hydrogen
chloride concentration of 15-20.2% and a pure hematite that will
undergo a physical separation step. Latent heat of condensation is
recovered to the pre-concentration and used as the heating input
with excess heat from the calcination stage (step 5).
[0453] The mother liquor from the hydrolyser (step 6) can be
recirculated partially to first step crystallization process where
an increase in concentration of non-hydrolysable elements is
observed. After iron removal, the liquor is rich in other
non-hydrolysable elements and mainly comprises magnesium chloride
or possible mixture of other elements (various chlorides) and rare
earth elements and rare metals that are, for example, still in the
form of chlorides.
[0454] Rare earth elements and rare metals in form of chlorides are
highly concentrated, in percentage, into the hydrolyser operational
unit (step 6) and are extracted from the mother liquor (step 10)
where various known techniques can be employed to extract a series
of individual RE-O (rare earth oxides). Among others, the processes
of the present disclosure allows to concentrate to high
concentration the following elements, within the hydrolyser:
scandium (Sc), galium (Ga), yttrium (Y), dysperosium (Dy), cerium
(Ce), praseodynium (Pr), neodynium (Nd), europium (Eu), lanthanum
(La), samarium (Sm), gadolinium, (Gd), erbium (Er), zirconium (Zr)
and mixtures of thereof. Technologies that can be used for
extracting rare earth elements and/or rare metals can be found, for
example, in Zhou et al. in RARE METALS, Vol. 27, No. 3, 2008, p
223-227, and in US 2004/0042945, hereby incorporated by reference
in their entirety. The person skilled in the art will also
understand that various other processes normally used for
extracting rare earth elements and/or rare metals from the Bayer
process can also be used. For example, various solvent extraction
techniques can be used. For certain elements, a technique involving
octylphenyl acid phosphate (OPAP) and toluene can be used. HCl can
be used as a stripping agent. This can be effective for recovering
Ce.sub.2O.sub.3, Sc.sub.2O.sub.3, Er.sub.2O.sub.3 etc. For example,
different sequence using oxalic acid and metallic iron for ferric
chloride separation can be used.
[0455] The spent acid liquor from steps 6 and 10 rich in value
added metals, mainly magnesium, is processed to step 7. The
solution is saturated with dry and highly concentrated gaseous
hydrogen chloride from step 5, which results in the precipitation
of magnesium chloride hexahydrate. For example, same can be
accomplished with HCl in aqueous form over 30% wt. The precipitate
retained, is fed to a calcination stage step 8 where pure MgO
(>98% wt.) is obtained and highly concentrated hydrochloric acid
(for example of at least 38%) is regenerated and diverted to the
leaching step (step 2). An alternative route for step 7 is using
dry gaseous hydrochloric acid from step 8.
[0456] In step 9, metal chlorides unconverted are processed to a
pyrohydrolysis step (700-900.degree. C.) to generate mixed oxides
and where hydrochloric acid from 15-20.2% wt. concentration can be
recovered.
[0457] According to another example as shown in FIG. 3, the
processes can be similar to the example shown in FIG. 1 but can
comprise some variants as below discussed.
[0458] In fact, as shown in FIG. 3, the processes can comprise
(after step 6 or just before step 10) an internal recirculation
back to the crystallization step 4. In such a case, The mother
liquor from the hydrolyser (step 6) can be recirculated fully or
partially to the crystallization of step 4 where a concentration
increase will occur with respect to the non-hydrolysable elements
including rare earth elements and/or rare metals.
[0459] Such a step can be useful for significantly increasing the
concentration of rare earth elements and/or rare metals, thereby
facilitating their extraction in step 10.
[0460] With respect to step 7, the solution rich in magnesium
chloride and other non-hydrolysable products at low temperature is,
as previously discussed, then brought up in concentration with dry
and highly concentrated gaseous hydrogen chloride by sparging it
into a crystallizer. This can result into the precipitation of
magnesium chloride as an hexahydrate (for example after sodium and
potassium chloride removal). This can also be accomplished with HCl
in aqueous form.
[0461] As shown in FIG. 3, an extra step 11 can be added. Sodium
chloride can undergo a chemical reaction with sulfuric acid so as
to obtain sodium sulfate and regenerate hydrochloric acid at a
concentration at or above the azeotropic point. Potassium chloride
can undergo a chemical reaction with sulfuric acid so as to obtain
potassium sulfate and regenerate hydrochloric acid at a
concentration above the azeotropic concentration. Sodium and
potassium chloride brine solution can be the feed material to
adapted small chlor-alkali electrolysis cells. In this latter case,
common bases (NaOH and KOH) and bleach (NaOCl and KOCl) are
produced and can be reused to some extent in other areas of the
processes of the present disclosure (scrubber, etc.).
[0462] The following are non-limitative examples.
EXAMPLE 1
Preparation of Alumina and Various Other Products
[0463] As a starting material a sample of clay was obtained from
the Grande Vallee area in Quebec, Canada.
[0464] These results represent an average of 80 tests carried out
from samples of about 900 kg each.
[0465] Crude clay in the freshly mined state after grinding and
classification had the following composition: [0466]
Al.sub.2O.sub.3: 15%-26%; [0467] SiO.sub.2: 45%-50%; [0468]
Fe.sub.2O.sub.3: 8%-9%; [0469] MgO: 1%-2%; [0470] Rare earth
elements and/or rare metals: 0.04%-0.07%; [0471] LOI: 5%-10%.
[0472] This material is thereafter leached in a two-stage procedure
at 140-170.degree. C. with 18-32 weight % HCl. The HCl solution was
used in a stoichiometric excess of 10-20% based on the
stoichiometric quantity required for the removal of the acid
leachable constituents of the clay. In the first leaching stage of
the semi-continuous operation (step 2), the clay was contacted for
2.5 hours with required amount or certain proportion of the total
amount of hydrochloric acid. After removal of the spent acid, the
clay was contacted again with a minimum 18 weight % hydrochloric
acid solution for about 1.5 hour at same temperature and
pressure.
[0473] A typical extraction curve obtained for both iron and
aluminum for a single stage leaching is shown in FIG. 2.
[0474] The leachate was filtered and the solid was washed with
water and analyzed using conventional analysis techniques (see step
3 of FIG. 1). Purity of obtained silica was of 95.4% and it was
free of any chlorides and of HCl.
[0475] In another example, the purity of the silica was 99.67%
through an extra leaching step.
[0476] After the leaching and silica removal, the concentration of
the various metal chlorides was: [0477] AlCl.sub.3: 15-20%; [0478]
FeCl.sub.2: 4-6%; [0479] FeCl.sub.3: 0.5-2.0%; [0480] MgCl.sub.2:
0.5-2.0%; [0481] REE-Cl: 0.1-2% [0482] Free HCl: 5-50 g/l
[0483] Spent acid was then crystallized using about 90 to about 98%
pure dry hydrochloric acid in gas phase in two stages with less
than 25 ppm iron in the aluminum chloride hexahydrate formed. The
concentration of HCl in solution (aqueous phase) was about 22 to
about 32% or 25 to about 32%, allowing 95.3% of Al.sub.2O.sub.3
recovery. The recovered crystallized material (hydrate form of
AlCl.sub.3 having a minimum purity of 99.8%) was then calcined at
930.degree. C. or 1250.degree. C., thus obtaining the a form of the
alumina. Heating at 930.degree. C. allows for obtaining the
beta-form of alumina while heating at 1250.degree. C. allows for
obtaining the alpha-form.
[0484] Another example was carried out at low temperature
(decomposition and calcination at about 350.degree. C.) and the a
form of the alumina was less than 2%.
[0485] HCl concentration in gas phase exiting the calcination stage
was having a concentration greater than 30% and was used (recycled)
for crystallization of the AlCl.sub.3 and MgCl.sub.2. Excess of
hydrochloric acid is absorbed at the required and targeted
concentration for the leaching steps.
[0486] Iron chloride (about 90-95% in ferric form) is then sent to
a hydrothermal process in view of its extraction as pure hematite
(Fe.sub.2O.sub.3). This can be done by using the technology
described in WO 2009/153321 of low temperature hydrolysis with full
heat recovery from calcining, pyrohydrolysis and leaching
stage.
[0487] Rare earth elements and rare metals are extracted from the
mother liquor of the hydrolyzer where silica, aluminum, iron and a
great portion of water have been removed and following
preconcentration from hydrolyser to crystallization. It was
observed that rare earth elements can be concentrated by a factor
of about 4.0 to 10.0 on average within the hydrolyzer itself on a
single pass through it i.e. without concentration loop. The
following concentration factors have been noted within the
hydrolyzer (single pass):
[0488] Ce>6
[0489] La>9
[0490] Nd>7
[0491] Y>9
[0492] Remaining magnesium chloride is sparged with dry and highly
concentrated hydrochloric acid and then calcinated to MgO while
recovering high concentration acid (for example up to 38.4%).
[0493] Mixed oxides (Me-O) containing other non-hydrolysable
components were then undergoing a pyrohydrolysis reaction at
700-800.degree. C. and recovered acid (15-20.2% wt.) was rerouted
for example to the leaching system.
Overall Yields Obtained:
[0494] Al.sub.2O.sub.3: 93.0-95.03% recovery; [0495]
Fe.sub.2O.sub.3: 92.65-99.5% recovery; [0496] Rare earth elements:
95% minimum recovery (mixture); [0497] MgO: 92.64-98.00% recovery;
[0498] Material discarded: 0-5% maximum; [0499] HCl global
recovery: 99.75% minimum; [0500] HCl strength as feed to leaching
15-32% (aqueous); 95% (gas) [0501] Red mud production: none.
EXAMPLE 2
Preparation of Alumina and Various Other Products
[0502] A similar feed material (bauxite instead of clay) was
processed as per in example 1 up to the leaching stage and revealed
to be easily leachable under the conditions established in example
1. It provided an extraction percentage of 100% for the iron and
over 90-95% for aluminum. The technology was found to be
economically viable and no harmful by-products (red mud) were
generated. Samples tested had various concentrations of
Al.sub.2O.sub.3 (up to 51%), Fe.sub.2O.sub.3 (up to 27%) and MgO
(up to 1.5%). Gallium extraction of 97.0% was observed. Scandium
extraction was 95%.
EXAMPLE 3
[0503] HCl Gas Enrichment and Purification: H.sub.2SO.sub.4
Route
[0504] H.sub.2SO.sub.4 can be used for carrying out purification of
HCl. It can be carried out by using a packing column with
H.sub.2SO.sub.4 flowing counter currently (see FIG. 4). This allows
for converting the recovered HCl into HCl having a concentration
above the azeotropic point (20.1% wt) and increase its
concentration by about 60 to about 70% at minimum.
[0505] Water is absorbed by H.sub.2SO.sub.4 and then
H.sub.2SO.sub.4 regeneration is applied where H.sub.2SO.sub.4 is
brought back to a concentration of about 95 to about 98% wt. Water
release at this stage free of sulphur is recycled back and used for
crystallization dissolution, etc. Packing of the column can
comprise polypropylene or polytrimethylene terephthalate (PTT).
[0506] Combustion energy can be performed with off gas preheating
air and oxygen enrichment. Oxygen enrichment: +2% represents flame
temperature increase by: 400.degree. C. maximum.
[0507] Thus, HCl of the processes of the present disclosure can
thus be treated accordingly.
EXAMPLE 4
HCl Gas Enrichment and Purification: Calcium Chloride to Calcium
Chloride Hexahydrate (Absorption/Desorption Process)
[0508] As shown in FIG. 5, CaCl.sub.2 can be used for drying HCl.
In fact, CaCl.sub.2 can be used for absorbing water contained into
HCl. In such a case, CaCl.sub.2 is converted into its hexachloride
form (CaCl.sub.2.6H.sub.2O) and one saturated system is eventually
switched into regeneration mode where hot air recovered from
calcination off gas of alumina and magnesium oxide spray roasting
is introduced to regenerate the fixed bed. Alternatively, other
absorbing agent such as LiCl can be used instead of CaCl.sub.2.
Such an ion/exchange type process can be seen in FIG. 4 and the
cycle can be inversed to switch from one column to another one.
[0509] The person skilled in the art would understand that the
processes described in examples 3 and 4 (see FIGS. 4 and 5) can be
used in various different manners. For example, these processes can
be combined with the various processes presented in the present
disclosure. For example, such purifications techniques can be
integrated to the processes shown in FIGS. 1, 3, 6, to 8 or 11 to
14. For example, these techniques can be used downstream of at
least one of step chosen from steps 5, 6, 8, 9, 10, 11, 13 and 20
(see FIGS. 1, 3, 8, 13 and 14). They can also be used downstream of
step 4 and/or step 7. They can also be used downstream of at least
one of step chosen from steps 104 to 111 (see FIGS. 6 and 7).
Moreover, they can be used in FIGS. 11 and 12 for example in steps
215, 216, 315 or 316.
EXAMPLE 5
Preparation of Alumina and Various Other Products
[0510] This example was carried out by using a process as
represented in FIGS. 6 and 7. It should be noted that the processes
represented in FIGS. 6 and 7 differ mainly by the fact that FIG. 7
shows an stage i.e. stage 112.
Raw Material Preparation
[0511] Raw material, clay for example, was processed in a secondary
crusher in the clay preparation plant 101. Dry milling and
classifying occurs on a dry basis in vertical roller mills (for
example Fuller-Loesche LM 30.41). The clay preparation 101 included
three roller mills; two running at a capacity of approximately
160-180 tph and one on standby. Raw material, if required, can be
reduced to 85% less than 63 microns. Processed material was then
stored in homogenization silos before being fed to the acid
leaching plant 102. Below in Table 1 are shown results obtained
during stage 101. If the ore contains the fluorine element, a
special treatment can be applied before carrying out the 102 stage.
In presence of hydrochloric acid, fluorine can produce hydrofluoric
acid. This acid is extremely corrosive and damaging for human
health. Thus, before leaching 102, an optional treatment fluorine
separation 112 can be done. Stage 112 can comprise treating the
processed material coming from stage 101 with an acid in a
pre-leaching treatment so as to remove hydrofluoric acid.
Therefore, depending on the composition of the raw material, a
fluorine separation stage 112 (or pre-leaching stage 112) can be
carried out.
TABLE-US-00001 TABLE 1 Clay preparation Rate 290 tph Composition
feed SiO.sub.2: 50.9% (main constituents) Al.sub.2O.sub.3: 24.0%
Fe.sub.2O.sub.3: 8.51% CaO: 0.48% MgO: 1.33% Na.sub.2O: 1.06%
K.sub.2O: 2.86% MnO: 0.16% Cr.sub.2O.sub.3: 0.01% TiO.sub.2: 0.85%
P.sub.2O.sub.5: 0.145% SrO: 0.015% BaO: 0.05% V.sub.2O.sub.5
0.0321% Other (including 9.63% H.sub.2O and REE): Obtained particle
size 85% < 63 .mu.m Residual moisture 0.5-0.7% Yield 99.5%
min
Acid Leaching
[0512] Next, acid leaching 102 was performed semi-continuously in
an 80 m.sup.3 glass-lined reactor. Semi-continuous mode comprises
replacing reacted acid 1/3 in the reaction period with higher
concentration regenerated acid, which greatly improves reaction
kinetics. The reactor arrangement comprises for example, a series
of three reactors. Other examples have been carried out with a
first leaching at 1 atm was carried out and then, a second and
third semi-continous or continuous leaching was carried out with
aqueous or gaseous HCl.
[0513] Leaching was performed at high temperature and pressure
(about 160 to about 195.degree. C. and pressures of about 5 to
about 8 barg) for a fixed period of time. Reaction time was a
function of the reaction extent targeted (98% for Al.sub.2O.sub.3),
leaching mode, acid strength, and temperature/pressure applied.
[0514] Spent acid recovered out of the acid leaching 102 was then
filtered 103 from unreacted silica and titanium dioxide and washed
through an automated filter press where all free HCl and chloride
are recovered. Step 113 can then be carried out in various manners
as indicated previously for step 13. This allows, for example, a
maximum quantity of about 30 ppm SiO.sub.2 going into spent liquor.
Cleaned silica at a concentration of .apprxeq.96%+SiO.sub.2 is then
produced. Various options are possible at that point. For example,
the 96% silica can undergo final neutralization through caustic
bath, cleaning, and then bricketing before storage. According to
another example, the silica purified by adding another leaching
step followed by a solid separation step that ensures TiO.sub.2
removal (see stage 113 in FIGS. 6 and 7). In that specific case,
high purity silica 99.5%+ is produced. In stage 113, titanium and
silicium can be separated from one another in various manners. For
example, the solid obtained from stage 103 can be leached in the
presence of MgCl.sub.2 at a temperature below 90 or 80.degree. C.
and at low acid concentration. For example, acid concentration can
be below 25 or 20%. The acid can be HCl or H.sub.2SO.sub.4. In such
a case, titanium remains soluble after such a leaching while
titanium is still in a solid form. The same also applies when the
solid is treated with Cl.sub.2. These solid and liquid obtained
after stage 113 are thus separated to provide eventually TiO.sub.2
and SiO.sub.2. Water input and flow for silica cleaning is in a
ratio of 1:1 (silica/water) (150 t/h SiO.sub.2/150 t/h H.sub.2O),
but comprises of wash water circulation in closed loop in the
process and limited amount of process water for final cleaning of
the silica and recovery of all chlorides and free HCl generated at
the leaching stage. Below in Table 2 are shown results obtained
during stage 102.
TABLE-US-00002 TABLE 2 Acid Leaching Equivalent solid feed rate
259.6 tph Operation mode Semi-continuous Acid to clay ratio 3.10 @
23% wt (Equivalent to 3.35 with semi-continuous at 18.0% wt)
Regenerated acid 18.0-32.0% concentration Operating temperature
150-155.degree. C. (Pilot) 165-200.degree. C. (Plant) MAWP 120 psig
Typical chemical Fe.sub.2O.sub.3 + 6 HCl .fwdarw. 2 FeCl.sub.3 +
3H.sub.2O reactions Al.sub.2O.sub.3 + 6 HCl .fwdarw. 2 AlCl.sub.3 +
3 H.sub.2O MgO + 2 HCl .fwdarw. MgCl.sub.2 + H.sub.2O K.sub.2O + 2
HCl .fwdarw. 2 KCl + H.sub.2O Re.sub.2O.sub.3 + 6 HCl .fwdarw. 2
ReCl.sub.3 + 3H.sub.2O Spent acid flow to 600-1100 m.sup.3/h
crystallization Practical chemical FeCl.sub.3 4.33% composition
after step FeCl.sub.2 0.19% 102 without solid (SiO.sub.2)
AlCl.sub.3 16.6% MgCl.sub.2 0.82% NaCl 1.1% KCl 1.2% CaCl.sub.2
0.26% Extraction yields Iron 100% Al.sub.2O.sub.3 .sup. 98%
SiO.sub.2 Recovery 99.997% Energy consumption Activation energy
only and self-sustained exothermic reaction from 130.degree. C.
AlCl.sub.3 Crystallization
[0515] Spent acid, with an aluminum chloride content of about 20 to
about 30%, was then processed in the crystallization stage 104. Dry
and highly concentrated HCl (>90% wt.) in gas phase was sparged
in a two-stage crystallization reactor, which allows the
crystallization of aluminum chloride hexahydrate.
[0516] The flow rate of acid through these reactors is about 600 to
about 675 m.sup.3/h and the reactor was maintained at about 50 to
about 60.degree. C. during this highly exothermic reaction. Heat
was recovered and exchanged to the acid purification 107 part of
the plant thus ensuring proper heat transfer and minimizing heat
consumption of the plant. Aluminum chloride solubility decreases
rapidly, compared to other elements, with the increase in
concentration of free HCl in the crystallization reactor. The
concentration of AlCl.sub.3 for precipitation/crystallization was
about 30%
[0517] The HCl concentration during crystallization was thus about
30 to about 32% wt.
[0518] The aqueous solution from the crystallization stage 104 was
then submitted to the hydrothermal acid recovery plant 105, while
the crystals are processed through the decomposition/calcination
stage in the calcination plant 106.
[0519] A one-step crystallization stage or a multi-step
crystallization stage can be done. For example, a two-steps
crystallization stage can be carried out.
[0520] Below in Tables 3A and 3B are shown results obtained during
stage 104.
TABLE-US-00003 TABLE 3A Aluminum chloride crystallization Number of
crystallization steps 2 Operating temperature 50-60.degree. C.
Sparging HCl concentration 90% (gaseous) Typical chemicals formed
AlCl.sub.3.cndot.6H.sub.2O (s) Metal chlorides (aq)
AlCl.sub.3.cndot.6H.sub.2O residual <5% (practical); 8%
TABLE-US-00004 TABLE 3B Typical crystals composition main
constituents obtained at pilot scale and feeding calcination
Component Weight distribution (%) AlCl.sub.3.cndot.6H.sub.2O 99.978
BaCl.sub.2.cndot.2H.sub.2O 0.0000 CaCl.sub.2.cndot.6H.sub.2O 0.0009
CrCl.sub.4 0.0022 CuCl.sub.2.cndot.2H.sub.2O 0.0000
FeCl.sub.3.cndot.6H.sub.2O 0.0019 KCl 0.0063
MgCl.sub.2.cndot.6H.sub.2O 0.0093 MnCl.sub.2.cndot.4H.sub.2O 0.0011
NaCl 0.0021 SiCl.sub.4 0.0004 SrCl.sub.2.cndot.6H.sub.2O 0.0000
TiCl.sub.4 0.0001 VCl.sub.4 0.0000 Free Cl.sup.- 0.0000
Calcination and Hydrothermal Acid Recovery
[0521] The calcination 106 comprises the use of a two-stage
circulating fluid bed (CFB) with preheating systems. The preheating
system can comprise a plasma torch to heat up steam to process. It
processes crystals in the decomposition/calcination stage. The
majority of the hydrochloric acid was released in the first stage
which was operated at a temperature of about 350.degree. C., while
the second stage performs the calcination itself. Acid from both
stages (about 66 to about 68% of the recovered acid from the
processes) was then recovered and sent to either to the acid
leaching 102 or to the acid purification 107. In the second
reactor, which was operated at a temperature of about 930.degree.
C., acid was recovered through the condensation and absorption into
two columns using mainly wash water from the acid leaching sector
102. Latent heat from this sector was recovered at the same time as
large amounts of water, which limits net water input.
[0522] In the iron oxides productions and acid recovery 105 system,
which comprises, aqueous solution from the crystallization 104
first undergoes a pre-concentration stage followed by processing in
the hydrolyzer reactor. Here, hematite was produced during low
temperature processing (about 165.degree. C.). A recirculation loop
was then taken from the hydrolyzer and is recirculated to the
pre-concentrator, allowing the concentration of REE, Mg, K, and
other elements. This recirculation loop, allows rare earth element
chlorides and/or rare metal chlorides and various metal chlorides
concentration to increase without having these products
precipitating with hematite up to a certain extent.
[0523] Depending on acid balance in the plant, recovered acid is
sent either directly to the 102 or 107 stage. Table 4 shows results
obtained in stage 105.
TABLE-US-00005 TABLE 4 Hydrothermal acid recovery Flowrate from
crystallization to HARP 592 m.sup.3/h (design) 600 m.sup.3/h
(design) Operating hydrolyser temperature 155-170.degree. C.
Regenerated acid concentration 27.4% Regenerated acid flowrate
205.2 tph HCl Hematite total production rate 24 TPH (design) HCl
recovery >99.8% Reflux (recirculation loop) rate in between 56
tph hydrolyzer and preconcentrator Rare earth element chlorides
and/or rare .apprxeq.12.8 t/h metal chlorides rate in recirculation
loop Hematite quality obtained and/or projected Fe.sub.2O.sub.3
purity >99.5% Hydrolysable chlorides <0.2% Moisture Max 20%
after filtration PSD 25-35 microns Density (bulk) 2-3 kg/l Typical
chemical reaction in stage 105 2FeCl.sub.3 + 3H.sub.2O .fwdarw.
Fe.sub.2O.sub.3 + 6 HCl 155-170.degree. C.
[0524] Table 5 shows results obtained in stage 106.
TABLE-US-00006 TABLE 5 Calcination Plant 106 Process
characteristics: Two-stage circulating fluid bed (CFB) with
pre-heating system Two-stage hydrochloric acid regeneration
Production rate (practical) About 66 tph CFB feed rate 371 tph @
2-3% humidity* Typical chemical reaction occurring
2(AlCl.sub.3.cndot.6 H.sub.2O) + Energy .fwdarw. Al.sub.2O.sub.3 +
6 HCl + 9H.sub.2O Typical alumina chemical composition obtained
from aluminum chloride hexahydrate crystals being fed to
calcination Component Weight distribution (%) Al.sub.2O.sub.3
99.938 Fe.sub.2O.sub.3 0.0033 SiO.sub.2 0.0032 Cr.sub.2O.sub.3
0.0063 V.sub.2O.sub.5 0.0077 Na 0.0190 MgO 0.0090 P.sub.2O.sub.5
0.0039 K 0.0053 Ca 0.0020 MnO 0.0002 Free Cl.sup.- Undetectable
Rare Earth Elements and Rare Metals Extractions
[0525] The stream that was taken out of 105 recirculation then was
treated for rare earth elements and are metals extraction 108, in
which the reduction of the remaining iron back to iron 2
(Fe.sup.2+), followed by a series of solvent extraction stages, was
performed. The reactants were oxalic acid, NaOH, DEHPA
(Di-(2-ethylhexyl)phosphoric acid) and TBP (tri-n-butyl phosphate)
organic solution, kerosene, and HCl were used to convert rare earth
element chlorides and rare metals chlorides to hydroxides.
Countercurrent organic solvent with stripping of solution using HCl
before proceeding to specific calcination from the rare earth
elements and rare metals in form of hydroxide and conversion to
high purity individual oxides. A ion exchange technique is also
capable of achieving same results as polytrimethylen terephtalate
(PET) membrane.
[0526] Iron powder from 105, or scrap metal as FeO, can be used at
a rate dependent on Fe.sup.3+ concentration in the mother liquor.
HCl (100% wt) at the rate of 1 tph can be required as the stripped
solution in REE Solvent Extraction (SX) separation and re-leaching
of rare earth elements and/or rare metals oxalates.
[0527] Water of very high quality, demineralized or nano, at the
rate of 100 tph was added to the strip solution and washing of
precipitates.
[0528] Oxalic acid as di-hydrate at a rate of 0.2 tph was added and
contributes to the rare earth elements and rare metals oxalates
precipitation. NaOH or MgOH at a rate of 0.5 tph can be used as a
neutralization agent.
[0529] DEHPA SX organic solution at the rate of 500 g/h was used as
active reagent in rare earth elements separation while TBP SX
organic solution at the rate of 5 kg/h is used as the active
reagent for gallium recovery and yttrium separation. Finally, a
kerosene diluent was used at the rate of approximately 2 kg/h in
all SX section. Calcination occurs in an electric rotary furnace
via indirect heating to convert contents to REE.sub.2O.sub.3
(oxides form) and maintain product purity.
[0530] Results of various tests made regarding stage 108 are shown
in Table 6.
TABLE-US-00007 TABLE 6 One line divided in subsections (5) to
isolate the following elements using solvent extraction:
Ga.sub.2O.sub.3 Y.sub.2O.sub.3 Sc.sub.2O.sub.3 Eu.sub.2O.sub.3 +
Er.sub.2O.sub.3 + Dy.sub.2O.sub.3 Ce.sub.2O.sub.3 + Nd.sub.2O.sub.3
+ Pr.sub.2O.sub.3 Equivalent output earths oxides 166.14 kg/h
Projected production as per pilot testing results Incoming Final
extraction Feed (kg/h) individual (kg/h) Ga.sub.2O.sub.3 15.66
11.98 Sc.sub.2O.sub.3 9.06 8.11 Y.sub.2O.sub.3 22.56 20.22
La.sub.2O.sub.3 32.24 25.67 Ce.sub.2O.sub.3 61.37 51.82
Pr.sub.2O.sub.3 8.08 6.18 Nd.sub.2O.sub.3 30.3 27.24
Sm.sub.2O.sub.3 5.7 4.51 Eu.sub.2O.sub.3 1.06 0.95 Gd.sub.2O.sub.3
4.5 4.06 Dy.sub.2O.sub.3 3.9 3.55 Er.sub.2O.sub.3 2.1 1.86 Total
196.55 166.14 Global yield: 84.53%
[0531] Alternatively, stage 108 can be carried out as described in
WO/2012/126092 and/or WO/2012/149642, that are hereby incorporated
by reference in their entirety.
[0532] The solution after stages 108 and 109 contained mainly
MgCl.sub.2, NaCl, KCl, CaCl.sub.2, FeCl.sub.2/FeCl.sub.3, and
AlCl.sub.3 (traces), and then undergoes the 111 stage. Na, K, Ca
that follows the MgO can be extracted in stage 110 by
crystallization in a specific order; Na first, followed by K, and
then Ca. This technique can be employed for example in the Israeli
Dead Sea salt processing plant to produce MgO and remove alkali
from the raw material.
HCl Regeneration
[0533] Alkali (Na, K), once crystallized, was sent and processed in
the alkali hydrochloric acid regeneration plant 110 for recovering
highly concentrated hydrochloric acid (HCl). The process chosen for
the conversion can generate value-added products
[0534] Various options are available to convert NaCl and KCl with
intent of recovering HCl. One example can be to contact them with
highly concentrated sulfuric acid (H.sub.2SO.sub.4), which
generates sodium sulphate (Na.sub.2SO.sub.4) and potassium sulfate
(K.sub.2SO.sub.4), respectively, and regenerates HCl at a
concentration above 90% wt. Another example, is the use of a sodium
and potassium chloride brine solution as the feed material to
adapted small chlor-alkali electrolysis cells. In this latter case,
common bases (NaOH and KOH) and bleach (NaOCl and KOCl) are
produced. The electrolysis of both NaCl and KCl brine is done in
different cells where the current is adjusted to meet the required
chemical reaction. In both cases, it is a two-step process in which
the brine is submitted to high current and base (NaOH or KOH) is
produced with chlorine (Cl.sub.2) and hydrogen (H.sub.2). H.sub.2
and Cl.sub.2 are then submitted to a common flame where highly
concentrated acid in gas (100% wt.) phase is produced and can be
used directly in the crystallization stage 104, or to
crystallization stages requiring dry highly concentrated acid.
Magnesium Oxide
[0535] The reduced flow, which was substantially free of most
elements (for example AlCl.sub.3, FeCl.sub.3, REE-Cl, NaCl, KCl)
and rich in MgCl.sub.2, was then submitted to the magnesium oxides
plant 111. In the MgO, pyrohydrolysis of MgCl.sub.2 and any other
leftover impurities were converted into oxide while regenerating
acid. The first step was a pre-evaporator/crystallizer stage in
which calcium is removed and converted into gypsum
(CaSO.sub.4.2H.sub.2O) by a simple chemical reaction with sulfuric
acid, for which separation of MgO is required. This increases the
capacity of MgO roasting and also energy consumption slightly,
while substantially recovering HCl. The next step was the specific
pyrohydrolysis of MgO concentrated solution by spray roasting. Two
(2) main products were generated; MgO that was further treated and
HCl (about 18% wt.), which was either recycled back to the upstream
leaching stage 102 or to the hydrochloric acid purification plant
(107) The MgO-product derived from the spray roaster can require
further washing, purification, and finally calcining depending on
the quality targeted. The purification and calcining can comprise a
washing-hydration step and standard calcining step.
[0536] The MgO from the spray roaster is highly chemically active
and was directly charged into a water tank where it reacts with
water to form magnesium hydroxide, which has poor solubility in
water. The remaining traces of chlorides, like MgCl.sub.2, NaCl,
dissolved in water. The Mg(OH).sub.2 suspension, after settling in
a thickener, was forwarded to vacuum drum filters, which remove the
remaining water. The cleaned Mg(OH).sub.2 is then forwarded into a
calcination reactor where it is exposed to high temperatures in a
vertical multi-stage furnace. Water from hydration is released and
allows the transformation of the Mg(OH).sub.2 to MgO and water. At
this point, the magnesium oxide was of high purity (>99%).
HCl Purification
[0537] The hydrochloric acid purification stage 107 is effective
for purifying HCl regenerated from different sectors (for example
105, 106, 111) and to increase its purity for crystallization,
whereas dry highly concentrated acid (>90% wt.) can be used as
the sparging agent. Stage 107 also allowed for controlling the
concentration of the acid going back to stage 102 (about 22 to
about 32% wt.) and allows total acid and water balance. Total plant
water balance is performed mainly by reusing wash water as
absorption medium, as quench agent or as dissolution medium at the
crystallization stages.
[0538] For example, HCl purification can be carried out as shown in
FIGS. 4 and 5.
[0539] For example, purification can be carried out by means of a
membrane distillation process. The membrane distillation process
applied here occurs when two aqueous liquids with different
temperatures are separated through a hydrophobic membrane. The
driving force of the process was supplied by the partial pressure
vapour difference caused by the temperature gradient between these
solutions. Vapour travels from the warm to the cold side. Without
wishing to be bound to such a theory, the separation mechanism was
based on the vapour/liquid equilibrium of the HCl/water liquid
mixture. Practical application of such a technology has been
applied to HCl/water, H.sub.2SO.sub.4/water systems and also on
large commercial scales on aqueous solution of sodium chloride with
the purpose of obtaining potable water from seawater and nano water
production. Therefore membrane distillation was a separation
process based on evaporation through a porous hydrophobic membrane.
The process was performed at about 60.degree. C. and was effective
to recover heat from the 104 and 102 stage with an internal water
circulation loop, in order to maintain a constant incoming
temperature to the membranes. For example, eight membranes of
300,000 m.sup.2 equivalent surface area can be used per membrane to
obtain a concentration of HCl well above the azeotropic point (i.e.
>36%) of the 750 m.sup.3/h and final 90% concentration is then
obtained through pressure distillation (rectification column).
[0540] Purification of HCl by processing thus regenerated acid
through hydrophobic membrane and separating water from HCl;
therefore increasing HCl concentration up to about 36% (above
azeotropic point) and therefore allowing with a single stage of
rectification through a pressure stripping column to obtain >90%
in gaseous phase, for crystallization stage (sparging); and
therefore controlling acid concentration into crystallization
stages up to 30-35%.sub.(aq).
[0541] As indicated stage 107 was operated at about 60.degree. C.
and heat input provided by heat recovery from stages 102 to 110.
Rectification column was operated at about 140.degree. C. in the
reboiler part. Net energy requirement was neutral (negative in fact
at -3.5 Gj/t Al.sub.2O.sub.3) since both systems were in
equilibrium and in balance.
[0542] For example, the acid purification can be carried out by
using adsorption technology over an activated alumina bed. In
continuous mode, at least two adsorption columns are required to
achieve either adsorption in one of them and regeneration in the
other one. Regeneration can be performed by feeding in
counter-current a hot or depressurized gas. This technology will
result in a purified gas at 100% wt.
[0543] For example, the acid purification can be made by using
calcium chloride as entrainer of water. A lean hydrochloric acid
solution is contacted with a strong calcium chloride solution
through a column. The water is then removed from the hydrochloric
acid solution and 99.9% gaseous HCl comes out of the process.
Cooling water and cryogenic coolant is used to condense water
traces in the HCl. The weak CaCl.sub.2 solution is concentrated by
an evaporator that ensures the recuperation of calcium chloride.
Depending on the impurities in the incoming HCl solution feed to
the column, some metals can contaminate the calcium chloride
concentrated solution. A precipitation with Ca(OH).sub.2 and a
filtration allows the removal of those impurities. The column can
operate for example at 0.5 barg. This technology can allow for the
recuperation of 98% of the HCl.
[0544] Table 7 shows the results obtained concerning the process
shown in FIG. 6.
TABLE-US-00008 Stage Stage Stage Stage Stage Stage TOTAL 101 102
106 105 MgO 107 108 PRODUCED Composition Yield Yield Yield Yield
Yield Yield Yield Yield (% wt) (%) (%) (%) (%) tpy (%) (%) (%) (%)
Main constituents SiO.sub.2 -- 99.997% -- -- -- -- -- -- 99.997% Al
-- 98.02% 95.03% -- -- -- -- -- 95.03% Fe -- 100.00% -- 92.65% --
-- -- -- 92.65% Mg -- 99.998% -- -- 29,756 92.64% -- -- 92.64% Ca
-- 99.998% -- -- -- -- -- -- 98.28% Na -- 99.998% -- -- -- -- -- --
92.76% K -- 100.00% -- -- -- -- -- -- 93.97% Others ind, H.sub.2O
-- -- -- -- -- -- -- -- RE/RM -- 99.80% -- 92.32% -- -- -- 84.67%
84.67% By-Products NaOH -- -- -- -- 68,556 -- -- -- -- NaOCl -- --
-- -- 9,269 -- -- -- -- KOH -- -- -- -- 73,211 -- -- -- -- KOCl --
-- -- -- 9,586 -- -- -- -- CaSO.sub.4 -- -- -- -- 46,837 -- -- --
-- Reactants H.sub.2SO.sub.4 (*) -- -- -- -- 19,204 -- -- -- --
Fresh HCl M-UP -- -- -- -- -- -- 99.75% -- 99.75% Total -- 98.55%
95.03% 256,419 92.64% 99.75% 84.67%
[0545] Tables 8 to 26 show results obtained concerning the products
made in accordance with the process shown in FIG. 6 in comparison
with standard of the industry.
TABLE-US-00009 TABLE 8 Chemical composition of obtained alumina
Standard used in Element % Weight* industry Al.sub.2O.sub.3 99.938
98.35 min Fe.sub.2O.sub.3 0.0033 0.0100 SiO.sub.2 0.0032 0.0150
TiO.sub.2 0.0003 0.0030 V.sub.2O.sub.5 0.0008 0.0020 ZnO 0.0005
0.0030 Cr.sub.2O.sub.3 0.0003 N/A MgO 0.0090 N/A MnO 0.0002 N/A
P.sub.2O.sub.5 0.0039 0.0010 Cu 0.0030 N/A Ca 0.0020 0.0030 Na
0.0190 0.4000 K 0.0053 0.0150 Li 0.0009 N/A Ba <0.00001 0.0000
Th <0.000001 0.0000 U <0.000001 0.0000 Free Cl.sup.- Not
detectable 0.0000 LOI <1.0000 <1.0000
[0546] P.sub.2O.sub.5 removal technique can include, for example,
after leaching, phosphorous precipitation using zirconium sulphate.
It can be provided, for example, in a solution heated at 80 to
about 90.degree. C. or about 85 to about 95.degree. C., under
vacuum.
TABLE-US-00010 TABLE 9 Physical properties of obtained alumina
Standard used in Property Orbite Alumina industry PSD < 20 .mu.m
5-10% N/A PSD < 45 .mu.m 10-12% <10% PSD > 75 .mu.m 50-60%
N/A SSA (m.sup.2/g) 60-85 60-80 Att. Index 10-12% <10% .alpha.
Al.sub.2O.sub.3 2-5% <7-9%
TABLE-US-00011 TABLE 10 Chemical composition of obtained hematite
Element % Weight Fe.sub.2O.sub.3 >99.5% Hydrolysable elements
<0.2%
TABLE-US-00012 TABLE 11 Physical properties of obtained hematite*
Property Orbite hematite PSD.sub.mean 25-35 .mu.m Density (bulk)
2000-3000 kg/m.sup.3 Humidity after filtration <10% *Material
can be produced as brickets
TABLE-US-00013 TABLE 12 Chemical composition of obtained silica
Element % Weight SiO.sub.2 >99.7 Al.sub.2O.sub.3 <0.25% MgO
.apprxeq.0.1% Fe.sub.2O.sub.3 .apprxeq.0.1% CaO .apprxeq.0.01%
Na.sub.2O <0.1% K.sub.2O <0.1% Note: Product may have
unbleached cellulose fiber filter aid. Cellulose wood flour.
TABLE-US-00014 TABLE 13 Physical properties of obtained silica
Property Orbite silica PSD.sub.mean 10-20 .mu.m Specific surface
area 34 m.sup.2/g Density (bulk) 2000-2500 kg/m.sup.3 Humidity
after filtration <30%
TABLE-US-00015 TABLE 14 Purity of obtained rare earth element
oxides Element Purity (%) Ga.sub.2O.sub.3 >99% Sc.sub.2O.sub.3
Y.sub.2O.sub.3 La.sub.2O.sub.3 Ce.sub.2O.sub.3 Pr.sub.2O.sub.3
Nd.sub.2O.sub.3 Sm.sub.2O.sub.3 Eu.sub.2O.sub.3 Gd.sub.2O.sub.3
Dy.sub.2O.sub.3 Er.sub.2O.sub.3 Physical properties of obtained
REE-O/RM-O Property Orbite REE-O/RM-O PSD.sub.mean 2-30 .mu.m
Density 5500-13000 kg/m.sup.3 LOI <1%
TABLE-US-00016 TABLE 15 Chemical composition of obtained MgO
Element Typical Specification MgO 99.0.sup.+ 98.35 min CaO 0.0020
0.83 SiO.sub.2 0.0000 0.20 max B.sub.2O.sub.3 0.0000 0.02 max
Al.sub.2O.sub.3 0.0300 0.12 max Fe.sub.2O.sub.3 0.0160 0.57 max
MnO.sub.2 <0.14 0.14 max LOI 0.7% <1%
TABLE-US-00017 TABLE 16 Physical properties of obtained MgO
Property Orbite MgO PSD.sub.mean 10 .mu.m Density N/A LOI 650
kg/m.sup.3
TABLE-US-00018 TABLE 17 Chemical composition of obtained NaOH
Element % Weight Sodium hydroxide 32% Water 68%
TABLE-US-00019 TABLE 18 Physical properties of obtained NaOH
Property Sodium hydroxide (NaOH) Physical state Liquid Vapour
pressure 14 mmHg Viscosity >1 Boiling point 100.degree. C.
Melting point 0.degree. C. Specific gravity 1.0
TABLE-US-00020 TABLE 19 Chemical composition of obtained sodium
hypochlorite (bleach) Element % Weight Sodium hypochlorite 12%
Sodium hydroxide <1% Water >80%
TABLE-US-00021 TABLE 20 Physical properties of obtained NaOCl
Property Sodium hypochlorite (NaOCl) Physical state Liquid Vapour
pressure 1.6 kPa Viscosity N/A Boiling point 100.degree. C. Melting
point -3.degree. C. Specific gravity 1.2
TABLE-US-00022 TABLE 21 Chemical composition of obtained potassium
hydroxide Element % Weight Potassium hydroxide 32% Water 68%
TABLE-US-00023 TABLE 22 Physical properties of obtained potassium
hydroxide Property KOH Physical state Liquid Vapour pressure 17.5
mmHg Viscosity N/A Boiling point 100.degree. C. Melting point N/A
Specific gravity 1.18
TABLE-US-00024 TABLE 23 Chemical composition of obtained potassium
hypochlorite (KOCl) Element % Weight Potassium hypochlorite 12%
Potassium hydroxide <1% Water >80%
TABLE-US-00025 TABLE 24 Physical properties of obtained potassium
hypochlorite Property KOCl Physical state Liquid Vapour pressure
N/A Viscosity N/A Boiling point 103.degree. C. Melting point N/A
Specific gravity >1.0
TABLE-US-00026 TABLE 25 Chemical composition of obtained calcium
sulphate dihydrate Element % Weight Calcium sulphate dihydrate
100%
TABLE-US-00027 TABLE 26 Physical properties of obtained calcium
sulphate dehydrate Property Orbite CaSO.sub.4.cndot.2H.sub.2O
Physical state Solid Specific gravity 2.32
[0547] In order to demonstrate the versatility of the processes of
the present disclosure, several other tests have been made so as to
shown that these processes can be applied to various sources of
starting material.
EXAMPLE 6
[0548] Another starting material has been used for preparing acidic
compositions comprising various components. In fact, a material
that is a concentrate of rare earth elements and rare metals
(particularly rich in zirconium) has been tested. Table 27 shows
the results carried out on such a starting material using a similar
process as shown in FIGS. 1, 3, 6, 7, 13 and 14 and as detailed in
Examples 1, 2 and 5. It can thus be inferred from the results shown
in Table 27 that the various components present in the leaching
(various metals such as aluminum, iron, magnesium as well as rare
earth elements and rare metals) can be extracted from the obtained
leaching composition and that they can eventually be isolated by
the processes of the present disclosure such as, for example, those
presented in Examples 1, 2 and 5.
EXAMPLE 7
[0549] Other tests have been made in a similar manner as described
in Example 6. In the present example, carbonatite has been used as
a starting material. (see Table 28 below).
TABLE-US-00028 TABLE 27 Tests made on a zirconium rich material.
Composition Average measure and/ measured Extraction O All Raw or
evaluated for testing rate measured Orbite process material (% wt.)
(% wt.) (ALP) (%) recovery (%) Al.sub.2O.sub.3 6.12 6.12 89.65
86.97 Fe.sub.2O.sub.3 15.80 15.80 99.50 97.51 SiO.sub.2 36.00 36.00
0.000 99.997 MgO 3.08 3.08 99.75 92.66 Na.sub.2O 1.13 1.13 99.50
99.50 K.sub.2O 2.12 2.12 99.50 99.50 CaO 6.10 6.10 99.50 99.00 S
total 0.22 0.22 100.00 F 1.98 1.98 99.50 99.00 TiO.sub.2 0.13 0.13
0.000 99.03 V.sub.2O.sub.5 0.00 0.00 98.00 96.04 P.sub.2O.sub.5
1.10 1.10 98.00 96.04 MnO 0.43 0.43 98.00 96.04 ZrO.sub.2 12.43
12.43 22.70 20.43 Cr.sub.2O.sub.3 0.00 0.00 0.00 0.00
Ce.sub.2O.sub.3 3.05 3.045 97.31 92.98 La.sub.2O.sub.3 1.34 1.337
99.55 92.68 Nd.sub.2O.sub.3 1.55 1.551 98.40 94.79 Pr.sub.2O.sub.3
0.37 0.375 99.75 97.52 Sm.sub.2O.sub.3 0.15 0.151 88.75 84.80
Dy.sub.2O.sub.3 0.09 0.089 80.35 76.77 Er.sub.2O.sub.3 0.03 0.030
72.60 69.37 Eu.sub.2O.sub.3 0.03 0.027 85.57 81.76 Gd.sub.2O.sub.3
0.21 0.205 82.85 79.16 Ho.sub.2O.sub.3 0.01 0.013 77.10 73.67
Lu.sub.2O.sub.3 0.00 0.003 60.15 57.47 Tb.sub.2O.sub.3 0.02 0.022
78.05 74.58 Th 0.02 0.022 88.10 84.18 Tm.sub.2O.sub.3 0.00 0.004
66.85 63.88 U 0.01 0.014 81.90 78.26 Y.sub.2O.sub.3 0.30 0.300
72.70 69.46 Yb.sub.2O.sub.3 0.02 0.023 62.80 60.01 Ga.sub.2O.sub.3
0.02 0.016 96.90 92.59 Sc.sub.2O.sub.3 0.00 0.003 95.00 90.77 LOI
(inc. 6.122023973 6.12 water)
TABLE-US-00029 TABLE 28 Tests made on carbonatite Composition
Average measure and/ measured Extraction O All Raw or evaluated for
testing rate measured Orbite process material (% wt.) (% wt.) (ALP)
(%) recovery (%) Al.sub.2O.sub.3 0.70 0.70 84.31 81.61
Fe.sub.2O.sub.3 11.22 11.22 94.14 92.15 SiO.sub.2 2.11 2.11 0.00003
99.997 MgO 6.50 6.500 100 96.25 Na.sub.2O 0.07 0.07 92.54 90.55
K.sub.2O 0.18 0.181 37.33 37.33 CaO 16.51 16.51 100 98.00 TiO.sub.2
0.00 0.000 0.00000 100.000 V.sub.2O.sub.5 0.00 0.000 0 100.000
P.sub.2O.sub.5 0.00 0.000 0 100.000 MnO 0.00 0.000 0 100.000
ZrO.sub.2 0.00 0.000 0 100.000 Cr.sub.2O.sub.3 0.00 0.000 0 100.000
Ce.sub.2O.sub.3 1.19 1.195 64.04 61.190 La.sub.2O.sub.3 0.46 0.463
63.86 61.018 Nd.sub.2O.sub.3 0.45 0.448 81.46 77.835
Pr.sub.2O.sub.3 0.14 0.142 67.59 64.582 Sm.sub.2O.sub.3 0.03 0.033
65.32 62.413 Dy.sub.2O.sub.3 0.00 0.000 78.12 74.644
Er.sub.2O.sub.3 0.00 0.000 86.15 82.316 Eu.sub.2O.sub.3 0.01 0.007
66.45 63.493 Gd.sub.2O.sub.3 0.01 0.013 54.46 52.037
Ho.sub.2O.sub.3 0.00 0.000 83.12 79.421 Lu.sub.2O.sub.3 0.00 0.000
88.86 84.906 Tb.sub.2O.sub.3 0.00 0.001 41.42 39.577 Th 0.06 0.065
Tm.sub.2O.sub.3 0.00 0.000 90.70 86.664 U 0.01 0.007 Y.sub.2O.sub.3
0.00 0.000 84.68 80.912 Yb.sub.2O.sub.3 0.00 0.000 85.11 81.323
Ga.sub.2O.sub.3 0.00 0.000 0 0.000 Sc.sub.2O.sub.3 0.00 0.000 0
0.000 LOI (inc. 60.33 water)
[0550] It can thus be inferred from the results shown in Table 28
that the various metals, rare earth elements and rare metals
extracted present in the obtained leaching composition can
eventually be isolated by the processes of the present disclosure
such as, for example, those presented in Examples 1, 2 and 5.
[0551] The process shown in FIG. 8 is similar to the process of
FIG. 1, with the exception that in FIG. 8, the term "aluminum" is
replaced by a "first metal". The person skilled in the art would
thus understand that in accordance with the present disclosure, the
processes can also encompass recovering various other products and
using various types of material as starting material. The first
metal can be chosen from Al, Fe, Ti, Zn, Ni, Co, Mg, Li, Mn, Cu,
Au, Ag, Pd, Pt. and mixtures thereof etc. Such a process can thus
be used for recovering various other metals than aluminum. Thus,
the first metal will be precipitated as a chloride in stage 5 and
eventually converted into an oxide.
[0552] In fact, the person skilled in the art would understand that
by replacing in FIGS. 1, 3, 6 and 7 the term "aluminum" with the
expression "first metal" the processes shown in these figures can
be used to obtain various other products than alumina and also used
for treating various different starting material. Thus, the first
metal can be recovered as a chloride (as it is the case for
aluminum chlorides in the processes of FIGS. 1, 3, 6, 7, 13 and 14)
and all the other stages of these processes can thus be carried out
(when applicable) depending on the nature of the starting material
used.
[0553] In step 4, the first metal chloride can be precipitated or
crystallized. In fact, the first metal can be removed from the
leachate in various manner. For example, a precipitating agent can
be added or HCl (for example gaseous) can be reacted with the
liquid obtained from step 3 so as to cause precipitation and/or
crytallization of the first metal chloride. Alternatively, the
temperature of the leachate can be controlled so as to
substantially selectively cause precipitation of the first metal
chloride.
[0554] As previously indicated, the processes of the present
disclosure can be efficient for treating material comprising Al,
Fe, Ti, Zn, Ni, Co, Mg, Li, Mn, Cu, Au, Ag, Pd, Pt.
[0555] For example, when treating a material that comprises, for
example, Mg and Fe, the material can be leached for example by
using HCl. Then, while the mixture (comprising a solid and a
liquid) so obtained is still hot, it can be treated so as to
separate the solid from the solid (for example by means of a
solid/liquid separation). That will be effective for removing
solids such as Si and optionally others such as Ti. Thus, the
liquid can be cooled down to a temperature of about 5 to about
70.degree. C., about 10 to about 60.degree. C., about 10 to about
50.degree. C., about 10 to about 40.degree. C., or about 15 to
about 30.degree. C. so as to substantially selectively precipitate
or crystalize magnesium (for example as MgCl.sub.2 (first metal
chloride in FIG. 8)), as shown in 4 of such a figure. Then, the
first metal chloride can be converted as shown in 5 so as to obtain
the first metal oxide. The iron can then be treated as in 6 of FIG.
8. The remainder of the process shown in FIG. 8 (stages 6 to 10)
being as described previously for FIG. 1.
[0556] Other examples of processes for treating material comprising
magnesium and iron can be as shown in FIGS. 13 and 14. The
processes of FIGS. 13 and 14 are similar to the processes of FIGS.
1 and 3, respectively. The main differences reside in steps 20 and
21 of FIGS. 13 and 14.
[0557] In these two examples of FIGS. 13 and 14 aluminum is also
treated. In fact, as it can be seen in stages 20 and 21 of FIGS. 13
and 14, Mg, Fe and Al, the material can be leached for example by
using HCl. Then, while the mixture (comprising a solid and a
liquid) so obtained is still hot, it can be treated so as to
separate the solid from the liquid (for example by means of a
solid/liquid separation (see stage 3)). That will be effective for
removing solids such as Si and optionally others such as Ti. Thus,
the liquid can be cooled down to a temperature of about 5 to about
70.degree. C., about 10 to about 60.degree. C., about 10 to about
50.degree. C., about 10 to about 40.degree. C., or about 15 to
about 30.degree. C. so as to substantially selectively precipitate
or crystalize magnesium (for example as MgCl.sub.2 (see stage 20 in
FIGS. 13 and 14)). Then, magnesium chloride can be converted into
magnesium oxide as shown in 21 of FIGS. 13 and 14. HCl can then be
recovered and treated as previously indicated The remainder of the
process shown in FIG. 13 (stages 4 to 10) are as described
previously for FIG. 1 and the remainder of the process shown in
FIG. 14 (stages 4 to 10) are as described previously for FIG.
3.
[0558] As previously indicated, magnesium can be firstly removed
from the leachate and then aluminum can be removed as shown in
FIGS. 13 and 14. Alternatively, aluminum can be firstly removed
from the leachate and then magnesium can be removed. In such a
case, steps 20 and 21 of FIGS. 13 and 14 would be disposed between
steps 4 and 6.
[0559] As another example, a mixture Ni/Co of a low concentration
in the feed (0.5-2.0% wt) can be leached with HCl according to FIG.
9. For example, leaching can be carried out by using HCl having a
concentration of about 18 to about 32 wt % in a first reactor then,
by using HCl having concentration of about 90 to about 95%
(gaseous) in a second reactor; and by optionally using HCl having
concentration of about 90 to about 95% (gaseous) in an optional
third reactor. Then selective crystallization with HCl bubbling,
solubility of chlorides (cobalt chloride vs nickel chloride) is
distinct based on HCl concentration. Hexahydrate chloride can then
be processed (produced) and fed for example to standard spray
roaster 600-640.degree. C. or fluid bed in view of producing
oxides. HCl can therefore be regenerated, sent to closed loop acid
purification where it is dried. Excess HCl can also be absorbed at
its isotropic point and be used to solvent extraction or leaching.
For example, nickel or cobalt chloride can thus replace aluminum
chloride in FIGS. 1, 3, 6, 7, 13 and 14. After the leaching, shown
in FIG. 9, the leachate can thus be treated as the leachate
described in the processes described in the present disclosure and
those of FIGS. 1, 3, 6, 7, 13 and 14, with the exception that
instead of aluminum chloride, nickel chloride or cobalt chloride
will be treated.
[0560] A similar approach can be adopted when using a starting
material that contains Mg and Li. Leaching can be carried out as
shown in FIG. 9 and selective precipitation of LiCl over MgCl.sub.2
or selective precipitation of MgCl.sub.2 over LiCl by injecting HCl
(for example gaseous HCl) can be done. Na can be removed by
crystallisation first. K can then be removed by crystallisation
Moreover, for further purification, LiCl and MgCl.sub.2 can be
separated by difference of solubility and/or crystallization in
water.
[0561] For example, platinum and palladium can also be treated
similarly. Moreover, their separation can also be accomplished with
ion exchange: selective crystallization in HCl is possible and can
be temperature sensitive.
[0562] FIGS. 10A and 10B show methods for separating Si from Ti.
For example, when using an ore as starting material, leaching can
be carried out in the presence of Cl.sub.2 (optionally in the
presence of carbon) so as to maintain Ti under the form of
TiCl.sub.4 since in remains in solution (fluid) while Si remains
solid (SiO.sub.2). Then, Ti (such as TiCl.sub.4) can be heated so
as to be converted into TiO.sub.2. For example, it can be injected
into a plasma torch for being purified.
[0563] Such a method for purifying Si and Ti can be used in all the
processes of the present disclosure when there is a need for
separating these two entities. See stage 13 in FIGS. 1, 3, 6, 7, 13
and 14 and stage 113 in FIG. 7.
[0564] The processes shown in FIGS. 11A, 11B, 12A and 12B are
processes that can be useful for treating various materials that
comprise, for example, Mg and other metals such as Ni and/or Co.
These materials can also comprise other metals such as aluminum,
iron etc. The processes of FIGS. 11A, 11B, 12A and 12B are similar,
with the exception that magnesium remains in solution after step
204 in FIG. 11A, while magnesium is precipitated after step 304 in
FIG. 12A.
[0565] Certain steps carried out in the processes of FIGS. 11A,
11B, 12A and 12 are similar to the steps of other processes
described in the present disclosure.
[0566] For example, steps 201 and 301 are similar to step 101 of
FIGS. 6 and 7. Moreover, steps 202 and 302 of FIGS. 11 and 12 are
similar to step 102 of FIGS. 6 and 7.
[0567] Steps 203 and 303 of FIGS. 11 and 12 are similar to step 103
of FIGS. 6 and 7.
[0568] Steps 213 and 313 of FIGS. 11 and 12 are similar to step 113
of FIG. 7. With respect to steps 214 and 314, TiO.sub.2 can
eventually be purified by means of a plasma torch.
[0569] Eventually, CaSO.sub.4.2H.sub.2O (gypsum) can be produced as
detailed in steps 223 and 323. Finally, pursuant to steps 224, 324,
225 and 325 Na.sub.2SO.sub.4 and K.sub.2SO.sub.4 can be
produced.
[0570] With respects to steps 213 and 313, TiO.sub.2 can be
converted into TiCl.sub.2 and/or TiCl.sub.4 so as to solubilize the
titanium. For example, this can be done by reacting TiO.sub.2
optionally with Cl.sub.2 and carbon (C) (see FIGS. 10A and 10B.
Therefore, SiO.sub.2 and titanium can be separated from one another
since SiO.sub.2 remains solid while titanium will be solubilized.
For example, steps 213, 313, 214 and 314 can be carried out as
detailed in FIG. 10.
[0571] Such processes are also efficient for achieving whole
recovery of HCl.
[0572] Pursuant to Ni and/or Co precipitation (steps 212 and 312)
LiOH can be precipitated and eventually washed in steps 208 and
308. Then, a further leaching can be carried out in steps 209 and
309 so as to extract further metals. For example, if the starting
material to be used in the processes of FIGS. 11 and 12 contains
aluminum, steps 210 and 310 can be carried out so as to precipitate
AlCl.sub.3. Such a step (210 or 310) is similar to step 104 carried
out in FIGS. 6 and 7. In an analogous manner, steps 205 and 305 of
FIGS. 11 and 12 are similar to step 105 of FIGS. 6 and 7. Steps 206
and 306 of FIGS. 11 and 12 are similar to step 106 of FIGS. 6 and
7. HCl purification carried out in steps 215 and 315 is similar to
step 107 carried out in FIGS. 6 and 7. As it can be seen in FIGS.
216 and 316, HCl is thus regenerated.
[0573] Alternatively, pursuant to step 209, and depending on the
composition of the starting material used for the processes of
FIGS. 11 and 12, steps 210 and 310 can be omitted or bypassed.
Therefore, if substantially no aluminum is comprised within the
starting material, or if the content in aluminum is considerably
low after step 209, step 249 can be carried out. The same also
applied to step 309 and 349 of FIG. 12. Then, pursuant to steps 249
and 349 of FIGS. 11 and 12 in which a mixture of various metal
chlorides are obtained, calcination can be carried out in steps 217
and 317 so as to eventually obtain a mixture of various metal
oxides.
[0574] Impurities obtained in steps 210 and 310 can be crystallized
in steps 218 and 318. By doing so, NaCl (steps 219 and 319) and KCl
(steps 221 and 321) can be crystallized. An electrolysis of NaCl
(steps 220 and 320) and KCl (steps 222 and 322) can be carried out
as previously indicated in the present disclosure.
EXAMPLE 8
[0575] Tests have been made for treating a magnesium-containing
material as starting material. The magnesium-containing material
was serpentine (asbestos) obtained from Black Lake, Quebec, Canada.
Tables 29 to 31 below shows results obtained when leaching such a
material with HCl. The serpentine ore was leached with a 30% molar
excess of HCl at a temperature of about 150 to about 160.degree.
C.
TABLE-US-00030 TABLE 29 Tests made on serpentine Asbestos 1
Asbestos 2 Asbestos 3 Asbestos 4 Mass In 880 800 1000 820 Mass Out
334 250 325 323 % water 35% 45% 45% 45% % Al Fe Na K Mg Ca Ti Si
Asbestos 1 Initial % 1.38 3.62 0.25 0.34 18.1 0.59 0.03 20.3
compound kg 12.144 31.856 2.2 2.992 159.28 5.192 0.264 178.64 Cake
% 1.87 1.11 0.33 0.3 6.49 0.16 0.01 34.8 kg 4.05977 2.40981 0.71643
0.6513 14.08979 0.34736 0.02171 75.5508 Yield % 67% 92% 67% 78% 91%
93% 92% 58% recovery Asbestos 2 Initial % 0.49 3.56 0.03 0.04 23.5
0.13 0.01 16.7 compound kg 3.92 28.48 0.24 0.32 188 1.04 0.08 133.6
Cake % 0.59 0.47 0.02 0.01 2.88 0.05 0.007 38.2 kg 0.81125 0.64625
0.0275 0.01375 3.96 0.06875 0.009625 52.525 Yield % 79% 98% 89% 96%
98% 93% 88% 61% recovery Asbestos 3 Initial % 0.58 4.13 0.16 0.08
22.3 0.23 0.01 17.3 compound kg 5.8 41.3 1.6 0.8 223 2.3 0.1 173
Cake % 0.06 0.44 0.01 0.01 3.27 0.02 0.01 34.3 kg 0.10725 0.7865
0.017875 0.017875 5.845125 0.03575 0.017875 61.31125 Yield % 98%
98% 99% 98% 97% 98% 82% 65% recovery Asbestos 4 Initial % 0.31 5.54
0.01 0.01 22.9 0.03 0.01 15.4 compound kg 2.542 45.428 0.082 0.082
187.78 0.246 0.082 126.28 Cake % 1.14 0.37 0.41 0.23 2.5 0.2 0.005
37.1 kg 2.02521 0.657305 0.728365 0.408595 4.44125 0.3553 0.0088825
65.90815 Yield % 20% 99% -788% -398% 98% -44% 89% 48% recovery
TABLE-US-00031 TABLE 30 Chemical Composition of Serpentine
Concentration measured Components and/or evaluated (% wt.)
Al.sub.2O.sub.3 0.59-2.61 Fe.sub.2O.sub.3 5.09-7.92 SiO.sub.2
32.94-43.43 MgO 30.01-38.97 Na.sub.2O 0.04-0.337 K.sub.2O
0.012-0.41 CaO 0.04-0.83 TiO.sub.2 0.017-0.050 V.sub.2O.sub.5 0.00
P.sub.2O.sub.5 0.00 MnO 0.005-0.080 ZrO 0.0000 F 0.00 Co 0.0000 Cr
0.076-0.101 Cd 0.0000 Zn 0.0000 Ni 0.0000 Cu 0.0000 Pb 0.0000 As
0.0000 Ga.sub.2O.sub.3 0.0000 Sc.sub.2O.sub.3 0.0000
Re.sub.2O.sub.3 0.00000 LOI (inc. water) 15.0-20.0
TABLE-US-00032 TABLE 31 Leaching of Serpentine - Recovery Yields
Components Leaching extraction rate (%) Al.sub.2O.sub.3 81.34
Fe.sub.2O.sub.3 96.70 SiO.sub.2 0.00003 MgO 96.01 Na.sub.2O 84.96
K.sub.2O 90.57 CaO 95.05 TiO.sub.2 0.00002 V.sub.2O.sub.5 0.00
P.sub.2O.sub.5 0.00 MnO 0.00 ZrO 0.00 F 0.00 Co 0.00 Cr 0.00 Cd
0.00 Zn 0.00 Ni 0.00 Cu 0.00 Pb 0.00 As 0.00
[0576] The results of Tables 29 to 31 thus show that the processes
of FIGS. 11 to 14 can be carried out with success.
[0577] It was also observed that when obtaining such a leachate by
leaching serpentine with HCl, it was possible to substantially
selectively precipitate some metals by controlling certain
parameters. In fact, it was found that magnesium chloride has a
very low solubility as compared with other chlorides (such as
AlCl.sub.3, FeCl.sub.3, CaCl.sub.2, NaCl, KCl, MnCl.sub.2, etc.),
for example when the leachate is at a temperature of about 10 to
about 60.degree. C., about 10 to about 40.degree. C., about 15 to
about 30.degree. C., about 15 to about 25.degree. C. or about
20.degree. C. (see FIGS. 16 and 17). Therefore, one possible way
among others of removing magnesium chloride in a substantially
selective manner was to leach serpentine and remove the unleached
solid while the mixture of solid and leachate is still hot. Then,
when the solid is removed, the leachate can be cooled down so as to
substantially selectively precipitate magnesium chloride.
[0578] Moreover, it was observed, during tests made, that when the
leachate has a concentration in HCl of about 16 to about 20%, about
17 to about 18%, or about 17.5% by weight, MgCl.sub.2 was
selectively precipitated over FeCl.sub.3 (see FIG. 15). It was also
observed that magnesium chloride can have a low solubility at a
temperature of about 15 to about 30.degree. C., about 15 to about
25.degree. C. or about 20.degree. C. (see FIGS. 16 and 17).
[0579] The process shown in FIG. 18 is similar to the process shown
in FIG. 1. The main difference resides in the fact that in the
process of FIG. 18 comprises stages 25 and 26 instead of stage 5 of
FIG. 1. In fact, in FIG. 18, the process comprises, after
crystallization of AlCl.sub.3, to convert AlCl.sub.3 into
Al(OH).sub.3 before calcining the latter product into
Al.sub.2O.sub.3. For example conversion of AlCl.sub.3 into
Al(OH).sub.3 can be carried out by reacting AlCl.sub.3 with a base
(for example KOH or NaOH). Calcination of Al(OH).sub.3 into
Al.sub.2O.sub.3 can be carried out at high temperature such as
about 800 to about 1200.degree. C. or about 1000 to about
1200.degree. C.
[0580] In fact, in the processes and the methods of the present
disclosure, calcination of AlCl.sub.3 can be replaced by
calcination of Al(OH).sub.3, as shown in FIG. 18 (see the
differences between the processes of FIG. 1 and FIG. 18). For
example, stages 25 and 26 can replace stage 5 of various processes
and methods such as shown in FIGS. 3, 8, 13 and 14 or stage 106 of
FIGS. 6 and 7.
[0581] The processes of the present disclosure provide a plurality
of important advantages and distinction over the known
processes.
[0582] The processes of the present disclosure provide fully
continuous and economical solutions that can successfully extract
alumina from various type of materials while providing ultra pure
secondary products of high added value including highly
concentrated rare earth elements and rare metals. The technology
described in the present disclosure allows for an innovative amount
of total acid recovery and also for a ultra high concentration of
recovered acid. When combing it to the fact that combined with a
semi-continuous leaching approach that favors very high extraction
yields and allows a specific method of crystallization of the
aluminum chloride and concentration of other value added elements.
These processes also allow for preparing aluminum with such a
produced alumina.
[0583] Specifically through the type of equipment used (for example
vertical roller mill) and its specific operation, raw material
grinding, drying and classifying can be applicable to various kinds
of material hardness (furnace slag for example), various types of
humidity (up to 30%) and incoming particle sizes. The particle size
established provides the advantage, at the leaching stage, of
allowing optimal contact between the minerals and the acid and then
allowing faster kinetics of reaction. Particles size employed
reduces drastically the abrasion issue and allows for the use of a
simplified metallurgy/lining when in contact with hydrochloric
acid.
[0584] A further advantage of the processes of the present
disclosure is the combined high temperature and high incoming
hydrochloric acid concentration. Combined with a semi continuous
operation where the free HCl driving force is used systematically,
iron and aluminum extraction yields do respectively reach 100% and
98% in less than about 40% of the reference time of a basic batch
process. Another advantage of higher HCl concentration than the
concentration at azeotropic point is the potential of capacity
increase. Again a higher HCl concentration than the concentration
of HCl at the azeotropic point and the semi-continuous approach
represent a substantial advance in the art. The same also applies
for continuous leaching.
[0585] Another advantage in that technique used for the mother
liquor separation from the silica after the leaching stage
countercurrent wash, is that band filters provide ultra pure silica
with expected purity exceeding 96%.
[0586] The crystallization of AlCl.sub.3 into AlCl.sub.3.6H.sub.2O
using dried, cleaned and highly concentrated gaseous HCl as the
sparging agent allows for a pure aluminum chloride hexahydrate with
only few parts per million of iron and other impurities. A minimal
number of stages are required to allow proper crystal growth.
[0587] The direct interconnection with the calcination of
AlCl.sub.3.6H.sub.2O into Al.sub.2O.sub.3 which does produce very
high concentration of gas allows the exact adjustment in continuous
of the HCl concentration within the crystallizer and thus proper
control of the crystal growth and crystallization process.
[0588] The applicants have now discovered fully integrated and
continuous processes with substantially total hydrochloric acid
recovery for the extraction of alumina and other value added
products from various materials that contain aluminum (clay,
bauxite, aluminosilicate materials, slag, red mud, fly ashes etc.)
containing aluminum. In fact, the processes allows for the
production of substantially pure alumina and other value added
products purified such as purified silica, pure hematite, pure
other minerals (ex: magnesium oxide) and rare earth elements
products. In addition, the processes do not require thermal
pre-treatment before the acid leach operation. Acid leach is
carried out using semi-continuous techniques with high pressure and
temperature conditions and very high regenerated hydrochloric acid
concentration. In addition, the processes do not generate any
residues not sellable, thus eliminating harmful residues to
environment like in the case of alkaline processes.
[0589] The advantage of the high temperature calcination stage, in
addition for allowing to control the a-form of alumina required, is
effective for providing a concentration of hydrochloric acid in the
aqueous form (>38%) that is higher than the concentration of HCl
at the azeotropic point and thus providing a higher incoming HCl
concentration to the leaching stage. The calcination stage
hydrochloric acid network can be interconnected to two (2)
crystallization systems and by pressure regulation excess HCl can
be being absorbed at the highest possible aqueous concentration.
The advantage of having a hexahydrate chloride with low moisture
content (<2%) incoming feed allows for a continuous basis to
recover acid at a concentration that is higher than the azeotropic
concentration. This HCl balance and double usage into three (3)
common parts of the processes and above azeotropic point is a
substantial advance in the art.
[0590] Another advantage is the use of the incoming chemistry
(ferric chloride) to the iron oxide and hydrochloric acid recovery
unit where all excess heat load from any calcination part,
pyrohydrolysis and leaching part is being recovered to
preconcentrate the mother liquor in metal chloride, thus allowing,
at very low temperature, the hydrolysis of the ferric chloride in
the form of very pure hematite and the acid regeneration at the
same concentration than at its azeotropic point.
[0591] A further major advantage of the instant process at the
ferric chloride hydrolysis step is the possibility to concentrate
rare earth elements in form of chlorides at very high concentration
within the hydrolyser reactor through an internal loop between
hydrolyzer and crystallization. The advantage in that the processes
of the present disclosure benefit from the various steps where
gradual concentration ratios are applied. Thus, at this stage, in
addition to an internal concentration loop, having the silica, the
aluminum, the iron and having in equilibrium a solution close to
saturation (large amount of water evaporated, no presence of free
hydrochloric acid) allows for taking rare earth elements and
non-hydrolysable elements in parts per million into the incoming
feed and to concentrate them in high percentage directly at the
hydrolyser after ferric chloride removal Purification of the
specific oxides (RE-O) can then be performed using various
techniques when in percentage levels. The advantage is doubled
here: concentration at very high level of rare earth elements using
integrated process stages and most importantly the approach
prevents from having the main stream (very diluted) of spent acid
after the leaching step with the risk of contaminating the main
aluminum chloride stream and thus affecting yields in
Al.sub.2O.sub.3. Another important improvement of the art is that
on top of being fully integrated, selective removal of components
allows for the concentration of rare earth elements to relatively
high concentration (percentages).
[0592] Another advantage of the process is again a selective
crystallization of MgCl.sub.2 through the sparging of HCl from
either the alumina calcination step or the magnesium oxide direct
calcination where in both cases highly concentrated acid both in
gaseous phase or in aqueous form are being generated. As previously
indicated, Mg(OH).sub.2 can also be obtained. As per aluminum
chloride specific crystallization, the direct interconnection with
the calcination reactor, the HCl gas very high concentration (about
85 to about 95%, about 90 to 95% or about 90% by weight) allows for
exact adjustment in continuous of the crystallizer based on quality
of magnesium oxide targeted. Should this process step (MgO
production or other value added metal oxide) be required based on
incoming process feed chemistry, the rare earth elements extraction
point then be done after this additional step; the advantage being
the extra concentration effect applied.
[0593] The pyrohydrolysis allows for the final conversion of any
remaining chloride and the production of refined oxides that can be
used (in case of clay as starting material) as a fertilizer and
allowing the processing of large amount of wash water from the
processes with the recovery hydrochloric acid in close loop at the
azeotropic point for the leaching step. The advantage of this last
step is related to the fact that it does totally close the process
loop in terms of acid recovery and the insurance that no residues
harmful to the environment are being generated while processing any
type of raw material, as previously described.
[0594] A major contribution to the art is that the proposed fully
integrated processes of the present disclosure is really allowing,
among others, the processing of bauxite in an economic way while
generating no red mud or harmful residues. In addition to the fact
of being applicable to other natural of raw materials (any suitable
aluminum-containing material or aluminous ores), the fact of using
hydrochloric acid total recovery and a global concentration that is
higher than the concentration at the azeotropic point (for example
about 21% to about 38%), the selective extraction of value added
secondary products and compliance (while remaining highly
competitive on transformation cost) with environmental
requirements, represent major advantages in the art.
[0595] It was thus demonstrated that the present disclosure
provides fully integrated processes for the preparation of pure
aluminum oxide using a hydrochloric acid treatment while producing
high purity and high quality products (minerals) and extracting
rare earth elements and rare metals.
[0596] With respect to the above-mentioned examples 1 to 5, the
person skilled in the art will also understand that depending on
the starting material used (for example, clays, argillite, bauxite,
kaolin, serpentine, kyanite nepheline, aluminosilicate materials,
mudstone, beryl, cryolite, garnet, spinel, niccolite, kamacite,
taenite, limonite, garnierite, laterite, pentlandite, smithsonite,
warikahnite, sphalerite, chalcopyrite, chalcocite, covellite,
bornite, tetrahedrite, malachite, azurite, cuprite, chrysocolla,
ecandrewsite, geikielite, pyrophanite, ilmenite, red mud, slag, fly
ashes, industrial refractory materials etc.,) some parameters might
need to be adjusted consequently. In fact, for example, certain
parameters such as reaction time, concentration, temperature may
vary in accordance with the reactivity of the selected starting
material.
[0597] While a description was made with particular reference to
the specific embodiments, it will be understood that numerous
modifications thereto will appear to those skilled in the art.
Accordingly, the above description and accompanying drawings should
be taken as specific examples and not in a limiting sense.
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